externals: Add catch2 v3.2.1

Merge commit '6879e5bb1c598a9a517d7bdec8ba1a0bace3ef10' as 'externals/catch'

externals/catch/.bazelrc

@@ -0,0 +1,10 @@
+build --enable_platform_specific_config
+
+build:gcc9 --cxxopt=-std=c++2a
+build:gcc11 --cxxopt=-std=c++2a
+build:clang13 --cxxopt=-std=c++17
+build:vs2019 --cxxopt=/std:c++17
+build:vs2022 --cxxopt=/std:c++17
+
+build:windows --config=vs2022
+build:linux --config=gcc11

externals/catch/.clang-format

@@ -0,0 +1,44 @@
+---
+Language: Cpp
+Standard: c++14
+
+# Note that we cannot use IncludeIsMainRegex functionality, because it
+# does not support includes in angle brackets (<>)
+SortIncludes: True
+IncludeBlocks: Regroup
+IncludeCategories:
+  - Regex: '<catch2/.*\.hpp>'
+    Priority: 1
+  - Regex: '<.*/.*\.hpp>'
+    Priority: 2
+  - Regex: '<.*>'
+    Priority: 3
+
+
+AllowShortBlocksOnASingleLine: Always
+AllowShortEnumsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: All
+AllowShortIfStatementsOnASingleLine: WithoutElse
+AllowShortLambdasOnASingleLine: Inline
+
+AccessModifierOffset: '-4'
+AlignEscapedNewlines: Left
+AllowAllConstructorInitializersOnNextLine: 'true'
+BinPackArguments: 'false'
+BinPackParameters: 'false'
+BreakConstructorInitializers: AfterColon
+ConstructorInitializerAllOnOneLineOrOnePerLine: 'true'
+DerivePointerAlignment: 'false'
+FixNamespaceComments: 'true'
+IndentCaseLabels: 'false'
+IndentPPDirectives: AfterHash
+IndentWidth: '4'
+NamespaceIndentation: All
+PointerAlignment: Left
+SpaceBeforeCtorInitializerColon: 'false'
+SpaceInEmptyParentheses: 'false'
+SpacesInParentheses: 'true'
+TabWidth: '4'
+UseTab: Never
+
+...

externals/catch/.conan/build.py

@@ -0,0 +1,94 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+import os
+import re
+from cpt.packager import ConanMultiPackager
+from cpt.ci_manager import CIManager
+from cpt.printer import Printer
+
+
+class BuilderSettings(object):
+    @property
+    def username(self):
+        """ Set catchorg as package's owner
+        """
+        return os.getenv("CONAN_USERNAME", "catchorg")
+
+    @property
+    def login_username(self):
+        """ Set Bintray login username
+        """
+        return os.getenv("CONAN_LOGIN_USERNAME", "horenmar")
+
+    @property
+    def upload(self):
+        """ Set Catch2 repository to be used on upload.
+            The upload server address could be customized by env var
+            CONAN_UPLOAD. If not defined, the method will check the branch name.
+            Only devel or CONAN_STABLE_BRANCH_PATTERN will be accepted.
+            The devel branch will be pushed to testing channel, because it does
+            not match the stable pattern. Otherwise it will upload to stable
+            channel.
+        """
+        return os.getenv("CONAN_UPLOAD", "https://api.bintray.com/conan/catchorg/catch2")
+
+    @property
+    def upload_only_when_stable(self):
+        """ Force to upload when running over tag branch
+        """
+        return os.getenv("CONAN_UPLOAD_ONLY_WHEN_STABLE", "True").lower() in ["true", "1", "yes"]
+
+    @property
+    def stable_branch_pattern(self):
+        """ Only upload the package the branch name is like a tag
+        """
+        return os.getenv("CONAN_STABLE_BRANCH_PATTERN", r"v\d+\.\d+\.\d+")
+
+    @property
+    def reference(self):
+        """ Read project version from branch create Conan reference
+        """
+        return os.getenv("CONAN_REFERENCE", "catch2/{}".format(self._version))
+
+    @property
+    def channel(self):
+        """ Default Conan package channel when not stable
+        """
+        return os.getenv("CONAN_CHANNEL", "testing")
+
+    @property
+    def _version(self):
+        """ Get version name from cmake file
+        """
+        pattern = re.compile(r"project\(Catch2 LANGUAGES CXX VERSION (\d+\.\d+\.\d+)\)")
+        version = "latest"
+        with open("CMakeLists.txt") as file:
+            for line in file:
+                result = pattern.search(line)
+                if result:
+                    version = result.group(1)
+        return version
+
+    @property
+    def _branch(self):
+        """ Get branch name from CI manager
+        """
+        printer = Printer(None)
+        ci_manager = CIManager(printer)
+        return ci_manager.get_branch()
+
+
+if __name__ == "__main__":
+    settings = BuilderSettings()
+    builder = ConanMultiPackager(
+        reference=settings.reference,
+        channel=settings.channel,
+        upload=settings.upload,
+        upload_only_when_stable=False,
+        stable_branch_pattern=settings.stable_branch_pattern,
+        login_username=settings.login_username,
+        username=settings.username,
+        test_folder=os.path.join(".conan", "test_package"))
+    builder.add()
+    builder.run()

externals/catch/.conan/test_package/CMakeLists.txt

@@ -0,0 +1,12 @@
+cmake_minimum_required(VERSION 3.2.0)
+project(test_package CXX)
+
+include("${CMAKE_BINARY_DIR}/conanbuildinfo.cmake")
+conan_basic_setup()
+
+find_package(Catch2 REQUIRED CONFIG)
+
+add_executable(${PROJECT_NAME} test_package.cpp)
+
+target_link_libraries(${PROJECT_NAME} Catch2::Catch2WithMain)
+set_target_properties(${PROJECT_NAME} PROPERTIES CXX_STANDARD 14)

externals/catch/.conan/test_package/conanfile.py

@@ -0,0 +1,20 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+from conans import ConanFile, CMake
+import os
+
+
+class TestPackageConan(ConanFile):
+    settings = "os", "compiler", "build_type", "arch"
+    generators = "cmake_find_package_multi", "cmake"
+
+    def build(self):
+        cmake = CMake(self)
+        cmake.configure()
+        cmake.build()
+
+    def test(self):
+        assert os.path.isfile(os.path.join(
+            self.deps_cpp_info["catch2"].rootpath, "licenses", "LICENSE.txt"))
+        bin_path = os.path.join("bin", "test_package")
+        self.run("%s -s" % bin_path, run_environment=True)

externals/catch/.conan/test_package/test_package.cpp

@@ -0,0 +1,13 @@
+#include <catch2/catch_test_macros.hpp>
+
+int Factorial( int number ) {
+    return number <= 1 ? 1 : Factorial( number - 1 ) * number;
+}
+
+TEST_CASE( "Factorial Tests", "[single-file]" ) {
+    REQUIRE( Factorial(0) == 1 );
+    REQUIRE( Factorial(1) == 1 );
+    REQUIRE( Factorial(2) == 2 );
+    REQUIRE( Factorial(3) == 6 );
+    REQUIRE( Factorial(10) == 3628800 );
+}

externals/catch/.gitattributes

@@ -0,0 +1,22 @@
+# This sets the default behaviour, overriding core.autocrlf
+* text=auto
+
+# All source files should have unix line-endings in the repository,
+# but convert to native line-endings on checkout
+*.cpp text
+*.h text
+*.hpp text
+
+# Windows specific files should retain windows line-endings
+*.sln text eol=crlf
+
+# Keep executable scripts with LFs so they can be run after being
+# checked out on Windows
+*.py text eol=lf
+
+
+# Keep the single include header with LFs to make sure it is uploaded,
+# hashed etc with LF
+single_include/**/*.hpp eol=lf
+# Also keep the LICENCE file with LFs for the same reason
+LICENCE.txt eol=lf

externals/catch/.github/FUNDING.yml

@@ -0,0 +1,2 @@
+github: "horenmar"
+custom: "https://www.paypal.me/horenmar"

externals/catch/.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,29 @@
+---
+name: Bug report
+about: Create an issue that documents a bug
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+**Describe the bug**
+A clear and concise description of what the bug is.
+
+**Expected behavior**
+A clear and concise description of what you expected to happen.
+
+**Reproduction steps**
+Steps to reproduce the bug.
+<!-- Usually this means a small and self-contained piece of code that uses Catch and specifying compiler flags if relevant. -->
+
+
+**Platform information:**
+<!-- Fill in any extra information that might be important for your issue. -->
+ - OS: **Windows NT**
+ - Compiler+version: **GCC v2.9.5**
+ - Catch version: **v1.2.3**
+
+
+**Additional context**
+Add any other context about the problem here.

externals/catch/.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,14 @@
+---
+name: Feature request
+about: Create an issue that requests a feature or other improvement
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+**Description**
+Describe the feature/change you request and why do you want it.
+
+**Additional context**
+Add any other context or screenshots about the feature request here.

externals/catch/.github/pull_request_template.md

@@ -0,0 +1,28 @@
+<!--
+Please do not submit pull requests changing the `version.hpp`
+or the single-include `catch.hpp` file, these are changed
+only when a new release is made.
+
+Before submitting a PR you should probably read the contributor documentation
+at docs/contributing.md. It will tell you how to properly test your changes.
+-->
+
+
+## Description
+<!--
+Describe the what and the why of your pull request. Remember that these two
+are usually a bit different. As an example, if you have made various changes
+to decrease the number of new strings allocated, that's what. The why probably
+was that you have a large set of tests and found that this speeds them up.
+-->
+
+## GitHub Issues
+<!-- 
+If this PR was motivated by some existing issues, reference them here.
+
+If it is a simple bug-fix, please also add a line like 'Closes #123'
+to your commit message, so that it is automatically closed.
+If it is not, don't, as it might take several iterations for a feature
+to be done properly. If in doubt, leave it open and reference it in the
+PR itself, so that maintainers can decide.
+-->

externals/catch/.github/workflows/linux-bazel-builds.yml

@@ -0,0 +1,24 @@
+name: Bazel build
+
+on: [push, pull_request]
+
+jobs:
+  build_and_test_ubuntu:
+    name: Linux Ubuntu 22.04 Bazel build <GCC 11.2.0>
+    runs-on: ubuntu-22.04
+    strategy:
+      matrix:
+        compilation_mode: [fastbuild, dbg, opt]
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Mount bazel cache
+      uses: actions/cache@v3
+      with:
+        path: "/home/runner/.cache/bazel"
+        key: bazel-ubuntu22-gcc11
+
+    - name: Build Catch2
+      run: |
+        bazelisk build --compilation_mode=${{matrix.compilation_mode}} //...

externals/catch/.github/workflows/linux-meson-builds.yml

@@ -0,0 +1,43 @@
+name: Linux builds (meson)
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    name: meson ${{matrix.cxx}}, C++${{matrix.std}}, ${{matrix.build_type}}
+    runs-on: ubuntu-22.04
+    strategy:
+      matrix:
+        cxx:
+          - g++-11
+          - clang++-11
+        build_type: [debug, release]
+        std: [14, 17]
+        include:
+          - cxx: clang++-11
+            other_pkgs: clang-11
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Prepare environment
+      run: sudo apt-get install -y meson ninja-build ${{matrix.other_pkgs}}
+
+    - name: Configure build
+      env:
+        CXX: ${{matrix.cxx}}
+        CXXFLAGS: -std=c++${{matrix.std}} ${{matrix.cxxflags}}
+      # Note: $GITHUB_WORKSPACE is distinct from ${{runner.workspace}}.
+      #       This is important
+      run: |
+        meson -Dbuildtype=${{matrix.build_type}} ${{runner.workspace}}/meson-build
+
+    - name: Build tests + lib
+      working-directory: ${{runner.workspace}}/meson-build
+      run: ninja
+
+    - name: Run tests
+      working-directory: ${{runner.workspace}}/meson-build
+      # Hardcode 2 cores we know are there
+      run: |
+        meson test --verbose

externals/catch/.github/workflows/linux-other-builds.yml

@@ -0,0 +1,104 @@
+# The builds in this file are more complex (e.g. they need custom CMake
+# configuration) and thus are unsuitable to the simple build matrix
+# approach used in simple-builds
+name: Linux builds (complex)
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    name: ${{matrix.build_description}}, ${{matrix.cxx}}, C++${{matrix.std}} ${{matrix.build_type}}
+    runs-on: ubuntu-20.04
+    strategy:
+      matrix:
+        # We add builds one by one in this case, because there are no
+        # dimensions that are shared across the builds
+        include:
+
+          # Single surrogate header build
+          - cxx: clang++-10
+            build_description: Surrogates build
+            build_type: Debug
+            std: 14
+            other_pkgs: clang-10
+            cmake_configurations: -DCATCH_BUILD_SURROGATES=ON
+
+          # Extras and examples with gcc-7
+          - cxx: g++-7
+            build_description: Extras + Examples
+            build_type: Debug
+            std: 14
+            other_pkgs: g++-7
+            cmake_configurations: -DCATCH_BUILD_EXTRA_TESTS=ON -DCATCH_BUILD_EXAMPLES=ON
+          - cxx: g++-7
+            build_description: Extras + Examples
+            build_type: Release
+            std: 14
+            other_pkgs: g++-7
+            cmake_configurations: -DCATCH_BUILD_EXTRA_TESTS=ON -DCATCH_BUILD_EXAMPLES=ON
+
+          # Extras and examples with Clang-10
+          - cxx: clang++-10
+            build_description: Extras + Examples
+            build_type: Debug
+            std: 17
+            other_pkgs: clang-10
+            cmake_configurations: -DCATCH_BUILD_EXTRA_TESTS=ON -DCATCH_BUILD_EXAMPLES=ON
+          - cxx: clang++-10
+            build_description: Extras + Examples
+            build_type: Release
+            std: 17
+            other_pkgs: clang-10
+            cmake_configurations: -DCATCH_BUILD_EXTRA_TESTS=ON -DCATCH_BUILD_EXAMPLES=ON
+
+          # Configure tests with Clang-10
+          - cxx: clang++-10
+            build_description: CMake configuration tests
+            build_type: Debug
+            std: 14
+            other_pkgs: clang-10
+            cmake_configurations: -DCATCH_ENABLE_CONFIGURE_TESTS=ON
+
+          # Valgrind test Clang-10
+          - cxx: clang++-10
+            build_description: Valgrind tests
+            build_type: Debug
+            std: 14
+            other_pkgs: clang-10 valgrind
+            cmake_configurations: -DMEMORYCHECK_COMMAND=`which valgrind` -DMEMORYCHECK_COMMAND_OPTIONS="-q --track-origins=yes --leak-check=full --num-callers=50 --show-leak-kinds=definite --error-exitcode=1"
+            other_ctest_args: -T memcheck -LE uses-python
+
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Prepare environment
+      run: sudo apt-get install -y ninja-build ${{matrix.other_pkgs}}
+
+    - name: Configure build
+      working-directory: ${{runner.workspace}}
+      env:
+        CXX: ${{matrix.cxx}}
+        CXXFLAGS: ${{matrix.cxxflags}}
+      # Note: $GITHUB_WORKSPACE is distinct from ${{runner.workspace}}.
+      #       This is important
+      run: |
+        cmake -Bbuild -H$GITHUB_WORKSPACE \
+              -DCMAKE_BUILD_TYPE=${{matrix.build_type}} \
+              -DCMAKE_CXX_STANDARD=${{matrix.std}} \
+              -DCMAKE_CXX_STANDARD_REQUIRED=ON \
+              -DCMAKE_CXX_EXTENSIONS=OFF \
+              -DCATCH_DEVELOPMENT_BUILD=ON \
+              ${{matrix.cmake_configurations}} \
+              -G Ninja
+
+    - name: Build tests + lib
+      working-directory: ${{runner.workspace}}/build
+      run: ninja
+
+    - name: Run tests
+      env:
+          CTEST_OUTPUT_ON_FAILURE: 1
+      working-directory: ${{runner.workspace}}/build
+      # Hardcode 2 cores we know are there
+      run: ctest -C ${{matrix.build_type}} -j 2 ${{matrix.other_ctest_args}}

externals/catch/.github/workflows/linux-simple-builds.yml

@@ -0,0 +1,122 @@
+name: Linux builds (basic)
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    name: ${{matrix.cxx}}, C++${{matrix.std}}, ${{matrix.build_type}}
+    runs-on: ubuntu-20.04
+    strategy:
+      matrix:
+        cxx:
+          - g++-5
+          - g++-6
+          - g++-7
+          - g++-8
+          - g++-9
+          - g++-10
+          - clang++-6.0
+          - clang++-7
+          - clang++-8
+          - clang++-9
+          - clang++-10
+        build_type: [Debug, Release]
+        std: [14]
+        include:
+          - cxx: g++-5
+            other_pkgs: g++-5
+          - cxx: g++-6
+            other_pkgs: g++-6
+          - cxx: g++-7
+            other_pkgs: g++-7
+          - cxx: g++-8
+            other_pkgs: g++-8
+          - cxx: g++-9
+            other_pkgs: g++-9
+          - cxx: g++-10
+            other_pkgs: g++-10
+          - cxx: clang++-6.0
+            other_pkgs: clang-6.0
+          - cxx: clang++-7
+            other_pkgs: clang-7
+          - cxx: clang++-8
+            other_pkgs: clang-8
+          - cxx: clang++-9
+            other_pkgs: clang-9
+          - cxx: clang++-10
+            other_pkgs: clang-10
+          # Clang 6 + C++17
+          # does not work with the default libstdc++ version thanks
+          # to a disagreement on variant implementation.
+          # - cxx: clang++-6.0
+          #   build_type: Debug
+          #   std: 17
+          #   other_pkgs: clang-6.0
+          # - cxx: clang++-6.0
+          #   build_type: Release
+          #   std: 17
+          #   other_pkgs: clang-6.0
+          # Clang 10 + C++17
+          - cxx: clang++-10
+            build_type: Debug
+            std: 17
+            other_pkgs: clang-10
+          - cxx: clang++-10
+            build_type: Release
+            std: 17
+            other_pkgs: clang-10
+          - cxx: clang++-10
+            build_type: Debug
+            std: 20
+            other_pkgs: clang-10
+          - cxx: clang++-10
+            build_type: Release
+            std: 20
+            other_pkgs: clang-10
+          - cxx: g++-10
+            build_type: Debug
+            std: 20
+            other_pkgs: g++-10
+          - cxx: g++-10
+            build_type: Release
+            std: 20
+            other_pkgs: g++-10
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Add repositories for older GCC
+      run: |
+        sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ bionic main'
+        sudo apt-add-repository 'deb http://azure.archive.ubuntu.com/ubuntu/ bionic universe'
+      if: ${{ matrix.cxx == 'g++-5' || matrix.cxx == 'g++-6' }}
+
+    - name: Prepare environment
+      run: sudo apt-get install -y ninja-build ${{matrix.other_pkgs}}
+
+    - name: Configure build
+      working-directory: ${{runner.workspace}}
+      env:
+        CXX: ${{matrix.cxx}}
+        CXXFLAGS: ${{matrix.cxxflags}}
+      # Note: $GITHUB_WORKSPACE is distinct from ${{runner.workspace}}.
+      #       This is important
+      run: |
+        cmake -Bbuild -H$GITHUB_WORKSPACE \
+              -DCMAKE_BUILD_TYPE=${{matrix.build_type}} \
+              -DCMAKE_CXX_STANDARD=${{matrix.std}} \
+              -DCMAKE_CXX_STANDARD_REQUIRED=ON \
+              -DCMAKE_CXX_EXTENSIONS=OFF \
+              -DCATCH_DEVELOPMENT_BUILD=ON \
+              -G Ninja
+
+    - name: Build tests + lib
+      working-directory: ${{runner.workspace}}/build
+      run: ninja
+
+    - name: Run tests
+      env:
+          CTEST_OUTPUT_ON_FAILURE: 1
+      working-directory: ${{runner.workspace}}/build
+      # Hardcode 2 cores we know are there
+      run: ctest -C ${{matrix.build_type}} -j 2

externals/catch/.github/workflows/mac-builds.yml

@@ -0,0 +1,52 @@
+name: Mac builds
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    # macos-12 updated to a toolchain that crashes when linking the
+    # test binary. This seems to be a known bug in that version,
+    # and will eventually get fixed in an update. After that, we can go
+    # back to newer macos images.
+    runs-on: macos-11
+    strategy:
+      matrix:
+        cxx:
+          - g++-11
+          - clang++
+        build_type: [Debug, Release]
+        std: [14, 17]
+        include:
+          - build_type: Debug
+            examples: ON
+            extra_tests: ON
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Configure build
+      working-directory: ${{runner.workspace}}
+      env:
+        CXX: ${{matrix.cxx}}
+        CXXFLAGS: ${{matrix.cxxflags}}
+      # Note: $GITHUB_WORKSPACE is distinct from ${{runner.workspace}}.
+      #       This is important
+      run: |
+        cmake -Bbuild -H$GITHUB_WORKSPACE \
+              -DCMAKE_BUILD_TYPE=${{matrix.build_type}} \
+              -DCMAKE_CXX_STANDARD=${{matrix.std}} \
+              -DCMAKE_CXX_STANDARD_REQUIRED=ON \
+              -DCATCH_DEVELOPMENT_BUILD=ON \
+              -DCATCH_BUILD_EXAMPLES=${{matrix.examples}} \
+              -DCATCH_BUILD_EXTRA_TESTS=${{matrix.examples}}
+
+    - name: Build tests + lib
+      working-directory: ${{runner.workspace}}/build
+      run: make -j 2
+
+    - name: Run tests
+      env:
+          CTEST_OUTPUT_ON_FAILURE: 1
+      working-directory: ${{runner.workspace}}/build
+      # Hardcode 2 cores we know are there
+      run: ctest -C ${{matrix.build_type}} -j 2

externals/catch/.github/workflows/validate-header-guards.yml

@@ -0,0 +1,36 @@
+name: Check header guards
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    # Set the type of machine to run on
+    runs-on: ubuntu-20.04
+    steps:
+
+      - name: Checkout source code
+        uses: actions/checkout@v2
+
+      - name: Setup Dependencies
+        uses: actions/setup-python@v2
+        with:
+            python-version: '3.7'
+      - name: Install checkguard
+        run: pip install guardonce
+
+      - name: Check that include guards are properly named
+        run: |
+          wrong_files=$(checkguard -r src/catch2/ -p "name | append _INCLUDED | upper")
+          if [[ $wrong_files ]]; then
+            echo "Files with wrong header guard:"
+            echo $wrong_files
+            exit 1
+          fi
+
+      - name: Check that there are no duplicated filenames
+        run: |
+          ./tools/scripts/checkDuplicateFilenames.py
+
+      - name: Check that all source files have the correct license header
+        run: |
+          ./tools/scripts/checkLicense.py

externals/catch/.gitignore

@@ -0,0 +1,37 @@
+*.build
+!meson.build
+*.pbxuser
+*.mode1v3
+*.ncb
+*.suo
+Debug
+Release
+*.user
+*.xcuserstate
+.DS_Store
+xcuserdata
+CatchSelfTest.xcscheme
+Breakpoints.xcbkptlist
+UpgradeLog.XML
+Resources/DWARF
+projects/Generated
+*.pyc
+DerivedData
+*.xccheckout
+Build
+.idea
+.vs
+.vscode
+cmake-build-*
+benchmark-dir
+.conan/test_package/build
+bazel-*
+build-fuzzers
+debug-build
+.vscode
+msvc-sln*
+# Currently we use Doxygen for dep graphs and the full docs are only slowly
+# being filled in, so we definitely do not want git to deal with the docs.
+docs/doxygen
+*.cache
+compile_commands.json

externals/catch/BUILD.bazel

@@ -0,0 +1,92 @@
+load("@bazel_skylib//rules:expand_template.bzl", "expand_template")
+
+expand_template(
+    name = "catch_user_config",
+    out = "catch2/catch_user_config.hpp",
+    substitutions = {
+        "@CATCH_CONFIG_CONSOLE_WIDTH@": "80",
+        "@CATCH_CONFIG_DEFAULT_REPORTER@": "console",
+        "#cmakedefine CATCH_CONFIG_ANDROID_LOGWRITE": "",
+        "#cmakedefine CATCH_CONFIG_BAZEL_SUPPORT": "#define CATCH_CONFIG_BAZEL_SUPPORT",
+        "#cmakedefine CATCH_CONFIG_COLOUR_WIN32": "",
+        "#cmakedefine CATCH_CONFIG_COUNTER": "",
+        "#cmakedefine CATCH_CONFIG_CPP11_TO_STRING": "",
+        "#cmakedefine CATCH_CONFIG_CPP17_BYTE": "",
+        "#cmakedefine CATCH_CONFIG_CPP17_OPTIONAL": "",
+        "#cmakedefine CATCH_CONFIG_CPP17_STRING_VIEW": "",
+        "#cmakedefine CATCH_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS": "",
+        "#cmakedefine CATCH_CONFIG_CPP17_VARIANT": "",
+        "#cmakedefine CATCH_CONFIG_DISABLE_EXCEPTIONS_CUSTOM_HANDLER": "",
+        "#cmakedefine CATCH_CONFIG_DISABLE_EXCEPTIONS": "",
+        "#cmakedefine CATCH_CONFIG_DISABLE_STRINGIFICATION": "",
+        "#cmakedefine CATCH_CONFIG_DISABLE": "",
+        "#cmakedefine CATCH_CONFIG_ENABLE_ALL_STRINGMAKERS": "",
+        "#cmakedefine CATCH_CONFIG_ENABLE_OPTIONAL_STRINGMAKER": "",
+        "#cmakedefine CATCH_CONFIG_ENABLE_PAIR_STRINGMAKER": "",
+        "#cmakedefine CATCH_CONFIG_ENABLE_TUPLE_STRINGMAKER": "",
+        "#cmakedefine CATCH_CONFIG_ENABLE_VARIANT_STRINGMAKER": "",
+        "#cmakedefine CATCH_CONFIG_EXPERIMENTAL_REDIRECT": "",
+        "#cmakedefine CATCH_CONFIG_FALLBACK_STRINGIFIER @CATCH_CONFIG_FALLBACK_STRINGIFIER@": "",
+        "#cmakedefine CATCH_CONFIG_FAST_COMPILE": "",
+        "#cmakedefine CATCH_CONFIG_GETENV": "",
+        "#cmakedefine CATCH_CONFIG_GLOBAL_NEXTAFTER": "",
+        "#cmakedefine CATCH_CONFIG_NO_ANDROID_LOGWRITE": "",
+        "#cmakedefine CATCH_CONFIG_NO_COLOUR_WIN32": "",
+        "#cmakedefine CATCH_CONFIG_NO_COUNTER": "",
+        "#cmakedefine CATCH_CONFIG_NO_CPP11_TO_STRING": "",
+        "#cmakedefine CATCH_CONFIG_NO_CPP17_BYTE": "",
+        "#cmakedefine CATCH_CONFIG_NO_CPP17_OPTIONAL": "",
+        "#cmakedefine CATCH_CONFIG_NO_CPP17_STRING_VIEW": "",
+        "#cmakedefine CATCH_CONFIG_NO_CPP17_UNCAUGHT_EXCEPTIONS": "",
+        "#cmakedefine CATCH_CONFIG_NO_CPP17_VARIANT": "",
+        "#cmakedefine CATCH_CONFIG_NO_GETENV": "",
+        "#cmakedefine CATCH_CONFIG_NO_GLOBAL_NEXTAFTER": "",
+        "#cmakedefine CATCH_CONFIG_NO_POSIX_SIGNALS": "",
+        "#cmakedefine CATCH_CONFIG_NO_USE_ASYNC": "",
+        "#cmakedefine CATCH_CONFIG_NO_WCHAR": "",
+        "#cmakedefine CATCH_CONFIG_NO_WINDOWS_SEH": "",
+        "#cmakedefine CATCH_CONFIG_NOSTDOUT": "",
+        "#cmakedefine CATCH_CONFIG_POSIX_SIGNALS": "",
+        "#cmakedefine CATCH_CONFIG_PREFIX_ALL": "",
+        "#cmakedefine CATCH_CONFIG_SHARED_LIBRARY": "",
+        "#cmakedefine CATCH_CONFIG_USE_ASYNC": "",
+        "#cmakedefine CATCH_CONFIG_WCHAR": "",
+        "#cmakedefine CATCH_CONFIG_WINDOWS_CRTDBG": "",
+        "#cmakedefine CATCH_CONFIG_WINDOWS_SEH": "",
+    },
+    template = "src/catch2/catch_user_config.hpp.in",
+)
+
+# Generated header library, modifies the include prefix to account for
+# generation path so that we can include <catch2/catch_user_config.hpp>
+# correctly.
+cc_library(
+    name = "catch2_generated",
+    hdrs = ["catch2/catch_user_config.hpp"],
+    include_prefix = ".",  # to manipulate -I of dependenices
+    visibility = ["//visibility:public"],
+)
+
+# Static library, without main.
+cc_library(
+    name = "catch2",
+    srcs = glob(
+        ["src/catch2/**/*.cpp"],
+        exclude = ["src/catch2/internal/catch_main.cpp"],
+    ),
+    hdrs = glob(["src/catch2/**/*.hpp"]),
+    includes = ["src/"],
+    linkstatic = True,
+    visibility = ["//visibility:public"],
+    deps = [":catch2_generated"],
+)
+
+# Static library, with main.
+cc_library(
+    name = "catch2_main",
+    srcs = ["src/catch2/internal/catch_main.cpp"],
+    includes = ["src/"],
+    linkstatic = True,
+    visibility = ["//visibility:public"],
+    deps = [":catch2"],
+)

externals/catch/CMake/Catch2Config.cmake.in

@@ -0,0 +1,10 @@
+@PACKAGE_INIT@
+
+
+# Avoid repeatedly including the targets
+if(NOT TARGET Catch2::Catch2)
+    # Provide path for scripts
+    list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}")
+
+    include(${CMAKE_CURRENT_LIST_DIR}/Catch2Targets.cmake)
+endif()

externals/catch/CMake/CatchConfigOptions.cmake

@@ -0,0 +1,79 @@
+
+#              Copyright Catch2 Authors
+# Distributed under the Boost Software License, Version 1.0.
+#   (See accompanying file LICENSE.txt or copy at
+#        https://www.boost.org/LICENSE_1_0.txt)
+
+# SPDX-License-Identifier: BSL-1.0
+
+##
+# This file contains options that are materialized into the Catch2
+# compiled library. All of them default to OFF, as even the positive
+# forms correspond to the user _forcing_ them to ON, while being OFF
+# means that Catch2 can use its own autodetection.
+#
+# For detailed docs look into docs/configuration.md
+
+
+macro(AddOverridableConfigOption OptionBaseName)
+  option(CATCH_CONFIG_${OptionBaseName} "Read docs/configuration.md for details" OFF)
+  option(CATCH_CONFIG_NO_${OptionBaseName} "Read docs/configuration.md for details" OFF)
+endmacro()
+
+macro(AddConfigOption OptionBaseName)
+  option(CATCH_CONFIG_${OptionBaseName} "Read docs/configuration.md for details" OFF)
+endmacro()
+
+set(_OverridableOptions
+  "ANDROID_LOGWRITE"
+  "BAZEL_SUPPORT"
+  "COLOUR_WIN32"
+  "COUNTER"
+  "CPP11_TO_STRING"
+  "CPP17_BYTE"
+  "CPP17_OPTIONAL"
+  "CPP17_STRING_VIEW"
+  "CPP17_UNCAUGHT_EXCEPTIONS"
+  "CPP17_VARIANT"
+  "GLOBAL_NEXTAFTER"
+  "POSIX_SIGNALS"
+  "USE_ASYNC"
+  "WCHAR"
+  "WINDOWS_SEH"
+  "GETENV"
+)
+
+foreach(OptionName ${_OverridableOptions})
+  AddOverridableConfigOption(${OptionName})
+endforeach()
+
+set(_OtherConfigOptions
+  "DISABLE_EXCEPTIONS"
+  "DISABLE_EXCEPTIONS_CUSTOM_HANDLER"
+  "DISABLE"
+  "DISABLE_STRINGIFICATION"
+  "ENABLE_ALL_STRINGMAKERS"
+  "ENABLE_OPTIONAL_STRINGMAKER"
+  "ENABLE_PAIR_STRINGMAKER"
+  "ENABLE_TUPLE_STRINGMAKER"
+  "ENABLE_VARIANT_STRINGMAKER"
+  "EXPERIMENTAL_REDIRECT"
+  "FAST_COMPILE"
+  "NOSTDOUT"
+  "PREFIX_ALL"
+  "WINDOWS_CRTDBG"
+)
+
+
+foreach(OptionName ${_OtherConfigOptions})
+  AddConfigOption(${OptionName})
+endforeach()
+set(CATCH_CONFIG_SHARED_LIBRARY ${BUILD_SHARED_LIBS})
+
+set(CATCH_CONFIG_DEFAULT_REPORTER "console" CACHE STRING "Read docs/configuration.md for details. The name of the reporter should be without quotes.")
+set(CATCH_CONFIG_CONSOLE_WIDTH "80" CACHE STRING "Read docs/configuration.md for details. Must form a valid integer literal.")
+
+# There is no good way to both turn this into a CMake cache variable,
+# and keep reasonable default semantics inside the project. Thus we do
+# not define it and users have to provide it as an outside variable.
+#set(CATCH_CONFIG_FALLBACK_STRINGIFIER "" CACHE STRING "Read docs/configuration.md for details.")

externals/catch/CMake/CatchMiscFunctions.cmake

@@ -0,0 +1,120 @@
+
+#              Copyright Catch2 Authors
+# Distributed under the Boost Software License, Version 1.0.
+#   (See accompanying file LICENSE.txt or copy at
+#        https://www.boost.org/LICENSE_1_0.txt)
+
+# SPDX-License-Identifier: BSL-1.0
+
+include(CheckCXXCompilerFlag)
+function(add_cxx_flag_if_supported_to_targets flagname targets)
+    string(MAKE_C_IDENTIFIER ${flagname} flag_identifier )
+    check_cxx_compiler_flag("${flagname}" HAVE_FLAG_${flag_identifier})
+
+    if (HAVE_FLAG_${flag_identifier})
+        foreach(target ${targets})
+            target_compile_options(${target} PRIVATE ${flagname})
+        endforeach()
+    endif()
+endfunction()
+
+# Assumes that it is only called for development builds, where warnings
+# and Werror is desired, so it also enables Werror.
+function(add_warnings_to_targets targets)
+    LIST(LENGTH targets TARGETS_LEN)
+    # For now we just assume 2 possibilities: msvc and msvc-like compilers,
+    # and other.
+    if (MSVC)
+        foreach(target ${targets})
+            # Force MSVC to consider everything as encoded in utf-8
+            target_compile_options( ${target} PRIVATE /utf-8 )
+            # Enable Werror equivalent
+            if (CATCH_ENABLE_WERROR)
+                target_compile_options( ${target} PRIVATE /WX )
+            endif()
+
+            # MSVC is currently handled specially
+            if ( CMAKE_CXX_COMPILER_ID MATCHES "MSVC" )
+                STRING(REGEX REPLACE "/W[0-9]" "/W4" CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS}) # override default warning level
+                target_compile_options( ${target} PRIVATE /w44265 /w44061 /w44062 /w45038 )
+            endif()
+        endforeach()
+
+    endif()
+
+    if (NOT MSVC)
+        set(CHECKED_WARNING_FLAGS
+          "-Wabsolute-value"
+          "-Wall"
+          "-Wc++20-compat"
+          "-Wcall-to-pure-virtual-from-ctor-dtor"
+          "-Wcast-align"
+          "-Wcatch-value"
+          "-Wdangling"
+          "-Wdeprecated"
+          "-Wdeprecated-register"
+          "-Wexceptions"
+          "-Wexit-time-destructors"
+          "-Wextra"
+          "-Wextra-semi"
+          "-Wfloat-equal"
+          "-Wglobal-constructors"
+          "-Winit-self"
+          "-Wmisleading-indentation"
+          "-Wmismatched-new-delete"
+          "-Wmismatched-return-types"
+          "-Wmismatched-tags"
+          "-Wmissing-braces"
+          "-Wmissing-declarations"
+          "-Wmissing-noreturn"
+          "-Wmissing-prototypes"
+          "-Wmissing-variable-declarations"
+          "-Wnull-dereference"
+          "-Wold-style-cast"
+          "-Woverloaded-virtual"
+          "-Wparentheses"
+          "-Wpedantic"
+          "-Wreorder"
+          "-Wreturn-std-move"
+          "-Wshadow"
+          "-Wstrict-aliasing"
+          "-Wsuggest-destructor-override"
+          "-Wsuggest-override"
+          "-Wundef"
+          "-Wuninitialized"
+          "-Wunneeded-internal-declaration"
+          "-Wunreachable-code"
+          "-Wunused"
+          "-Wunused-function"
+          "-Wunused-parameter"
+          "-Wvla"
+          "-Wweak-vtables"
+
+          # This is a useful warning, but our tests sometimes rely on
+          # functions being present, but not picked (e.g. various checks
+          # for stringification implementation ordering).
+          # Ergo, we should use it every now and then, but we cannot
+          # enable it by default.
+          # "-Wunused-member-function"
+        )
+        foreach(warning ${CHECKED_WARNING_FLAGS})
+            add_cxx_flag_if_supported_to_targets(${warning} "${targets}")
+        endforeach()
+
+        if (CATCH_ENABLE_WERROR)
+            foreach(target ${targets})
+                # Enable Werror equivalent
+                target_compile_options( ${target} PRIVATE -Werror )
+            endforeach()
+        endif()
+    endif()
+endfunction()
+
+# Adds flags required for reproducible build to the target
+# Currently only supports GCC and Clang
+function(add_build_reproducibility_settings target)
+  # Make the build reproducible on versions of g++ and clang that supports -ffile-prefix-map
+  if((CMAKE_CXX_COMPILER_ID STREQUAL "GNU") OR (CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
+    add_cxx_flag_if_supported_to_targets("-ffile-prefix-map=${CATCH_DIR}/=" "${target}")
+  endif()
+endfunction()

externals/catch/CMake/FindGcov.cmake

@@ -0,0 +1,157 @@
+# This file is part of CMake-codecov.
+#
+# Copyright (c)
+#   2015-2017 RWTH Aachen University, Federal Republic of Germany
+#
+# See the LICENSE file in the package base directory for details
+#
+# Written by Alexander Haase, alexander.haase@rwth-aachen.de
+#
+
+
+# include required Modules
+include(FindPackageHandleStandardArgs)
+
+
+# Search for gcov binary.
+set(CMAKE_REQUIRED_QUIET_SAVE ${CMAKE_REQUIRED_QUIET})
+set(CMAKE_REQUIRED_QUIET ${codecov_FIND_QUIETLY})
+
+get_property(ENABLED_LANGUAGES GLOBAL PROPERTY ENABLED_LANGUAGES)
+foreach (LANG ${ENABLED_LANGUAGES})
+	# Gcov evaluation is dependent on the used compiler. Check gcov support for
+	# each compiler that is used. If gcov binary was already found for this
+	# compiler, do not try to find it again.
+	if (NOT GCOV_${CMAKE_${LANG}_COMPILER_ID}_BIN)
+		get_filename_component(COMPILER_PATH "${CMAKE_${LANG}_COMPILER}" PATH)
+
+		if ("${CMAKE_${LANG}_COMPILER_ID}" STREQUAL "GNU")
+			# Some distributions like OSX (homebrew) ship gcov with the compiler
+			# version appended as gcov-x. To find this binary we'll build the
+			# suggested binary name with the compiler version.
+			string(REGEX MATCH "^[0-9]+" GCC_VERSION
+				"${CMAKE_${LANG}_COMPILER_VERSION}")
+
+			find_program(GCOV_BIN NAMES gcov-${GCC_VERSION} gcov
+				HINTS ${COMPILER_PATH})
+
+		elseif ("${CMAKE_${LANG}_COMPILER_ID}" STREQUAL "Clang")
+			# Some distributions like Debian ship llvm-cov with the compiler
+			# version appended as llvm-cov-x.y. To find this binary we'll build
+			# the suggested binary name with the compiler version.
+			string(REGEX MATCH "^[0-9]+.[0-9]+" LLVM_VERSION
+				"${CMAKE_${LANG}_COMPILER_VERSION}")
+
+			# llvm-cov prior version 3.5 seems to be not working with coverage
+			# evaluation tools, but these versions are compatible with the gcc
+			# gcov tool.
+			if(LLVM_VERSION VERSION_GREATER 3.4)
+				find_program(LLVM_COV_BIN NAMES "llvm-cov-${LLVM_VERSION}"
+					"llvm-cov" HINTS ${COMPILER_PATH})
+				mark_as_advanced(LLVM_COV_BIN)
+
+				if (LLVM_COV_BIN)
+					find_program(LLVM_COV_WRAPPER "llvm-cov-wrapper" PATHS
+						${CMAKE_MODULE_PATH})
+					if (LLVM_COV_WRAPPER)
+						set(GCOV_BIN "${LLVM_COV_WRAPPER}" CACHE FILEPATH "")
+
+						# set additional parameters
+						set(GCOV_${CMAKE_${LANG}_COMPILER_ID}_ENV
+							"LLVM_COV_BIN=${LLVM_COV_BIN}" CACHE STRING
+							"Environment variables for llvm-cov-wrapper.")
+						mark_as_advanced(GCOV_${CMAKE_${LANG}_COMPILER_ID}_ENV)
+					endif ()
+				endif ()
+			endif ()
+
+			if (NOT GCOV_BIN)
+				# Fall back to gcov binary if llvm-cov was not found or is
+				# incompatible. This is the default on OSX, but may crash on
+				# recent Linux versions.
+				find_program(GCOV_BIN gcov HINTS ${COMPILER_PATH})
+			endif ()
+		endif ()
+
+
+		if (GCOV_BIN)
+			set(GCOV_${CMAKE_${LANG}_COMPILER_ID}_BIN "${GCOV_BIN}" CACHE STRING
+				"${LANG} gcov binary.")
+
+			if (NOT CMAKE_REQUIRED_QUIET)
+				message("-- Found gcov evaluation for "
+				"${CMAKE_${LANG}_COMPILER_ID}: ${GCOV_BIN}")
+			endif()
+
+			unset(GCOV_BIN CACHE)
+		endif ()
+	endif ()
+endforeach ()
+
+
+
+
+# Add a new global target for all gcov targets. This target could be used to
+# generate the gcov files for the whole project instead of calling <TARGET>-gcov
+# for each target.
+if (NOT TARGET gcov)
+	add_custom_target(gcov)
+endif (NOT TARGET gcov)
+
+
+
+# This function will add gcov evaluation for target <TNAME>. Only sources of
+# this target will be evaluated and no dependencies will be added. It will call
+# Gcov on any source file of <TNAME> once and store the gcov file in the same
+# directory.
+function (add_gcov_target TNAME)
+	set(TDIR ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/${TNAME}.dir)
+
+	# We don't have to check, if the target has support for coverage, thus this
+	# will be checked by add_coverage_target in Findcoverage.cmake. Instead we
+	# have to determine which gcov binary to use.
+	get_target_property(TSOURCES ${TNAME} SOURCES)
+	set(SOURCES "")
+	set(TCOMPILER "")
+	foreach (FILE ${TSOURCES})
+		codecov_path_of_source(${FILE} FILE)
+		if (NOT "${FILE}" STREQUAL "")
+			codecov_lang_of_source(${FILE} LANG)
+			if (NOT "${LANG}" STREQUAL "")
+				list(APPEND SOURCES "${FILE}")
+				set(TCOMPILER ${CMAKE_${LANG}_COMPILER_ID})
+			endif ()
+		endif ()
+	endforeach ()
+
+	# If no gcov binary was found, coverage data can't be evaluated.
+	if (NOT GCOV_${TCOMPILER}_BIN)
+		message(WARNING "No coverage evaluation binary found for ${TCOMPILER}.")
+		return()
+	endif ()
+
+	set(GCOV_BIN "${GCOV_${TCOMPILER}_BIN}")
+	set(GCOV_ENV "${GCOV_${TCOMPILER}_ENV}")
+
+
+	set(BUFFER "")
+	foreach(FILE ${SOURCES})
+		get_filename_component(FILE_PATH "${TDIR}/${FILE}" PATH)
+
+		# call gcov
+		add_custom_command(OUTPUT ${TDIR}/${FILE}.gcov
+			COMMAND ${GCOV_ENV} ${GCOV_BIN} ${TDIR}/${FILE}.gcno > /dev/null
+			DEPENDS ${TNAME} ${TDIR}/${FILE}.gcno
+			WORKING_DIRECTORY ${FILE_PATH}
+		)
+
+		list(APPEND BUFFER ${TDIR}/${FILE}.gcov)
+	endforeach()
+
+
+	# add target for gcov evaluation of <TNAME>
+	add_custom_target(${TNAME}-gcov DEPENDS ${BUFFER})
+
+	# add evaluation target to the global gcov target.
+	add_dependencies(gcov ${TNAME}-gcov)
+endfunction (add_gcov_target)

externals/catch/CMake/FindLcov.cmake

@@ -0,0 +1,354 @@
+# This file is part of CMake-codecov.
+#
+# Copyright (c)
+#   2015-2017 RWTH Aachen University, Federal Republic of Germany
+#
+# See the LICENSE file in the package base directory for details
+#
+# Written by Alexander Haase, alexander.haase@rwth-aachen.de
+#
+
+
+# configuration
+set(LCOV_DATA_PATH "${CMAKE_BINARY_DIR}/lcov/data")
+set(LCOV_DATA_PATH_INIT "${LCOV_DATA_PATH}/init")
+set(LCOV_DATA_PATH_CAPTURE "${LCOV_DATA_PATH}/capture")
+set(LCOV_HTML_PATH "${CMAKE_BINARY_DIR}/lcov/html")
+
+
+
+
+# Search for Gcov which is used by Lcov.
+find_package(Gcov)
+
+
+
+
+# This function will add lcov evaluation for target <TNAME>. Only sources of
+# this target will be evaluated and no dependencies will be added. It will call
+# geninfo on any source file of <TNAME> once and store the info file in the same
+# directory.
+#
+# Note: This function is only a wrapper to define this function always, even if
+#   coverage is not supported by the compiler or disabled. This function must
+#   be defined here, because the module will be exited, if there is no coverage
+#   support by the compiler or it is disabled by the user.
+function (add_lcov_target TNAME)
+	if (LCOV_FOUND)
+		# capture initial coverage data
+		lcov_capture_initial_tgt(${TNAME})
+
+		# capture coverage data after execution
+		lcov_capture_tgt(${TNAME})
+	endif ()
+endfunction (add_lcov_target)
+
+
+
+
+# include required Modules
+include(FindPackageHandleStandardArgs)
+
+# Search for required lcov binaries.
+find_program(LCOV_BIN lcov)
+find_program(GENINFO_BIN geninfo)
+find_program(GENHTML_BIN genhtml)
+find_package_handle_standard_args(lcov
+	REQUIRED_VARS LCOV_BIN GENINFO_BIN GENHTML_BIN
+)
+
+# enable genhtml C++ demangeling, if c++filt is found.
+set(GENHTML_CPPFILT_FLAG "")
+find_program(CPPFILT_BIN c++filt)
+if (NOT CPPFILT_BIN STREQUAL "")
+	set(GENHTML_CPPFILT_FLAG "--demangle-cpp")
+endif (NOT CPPFILT_BIN STREQUAL "")
+
+# enable no-external flag for lcov, if available.
+if (GENINFO_BIN AND NOT DEFINED GENINFO_EXTERN_FLAG)
+	set(FLAG "")
+	execute_process(COMMAND ${GENINFO_BIN} --help OUTPUT_VARIABLE GENINFO_HELP)
+	string(REGEX MATCH "external" GENINFO_RES "${GENINFO_HELP}")
+	if (GENINFO_RES)
+		set(FLAG "--no-external")
+	endif ()
+
+	set(GENINFO_EXTERN_FLAG "${FLAG}"
+		CACHE STRING "Geninfo flag to exclude system sources.")
+endif ()
+
+# If Lcov was not found, exit module now.
+if (NOT LCOV_FOUND)
+	return()
+endif (NOT LCOV_FOUND)
+
+
+
+
+# Create directories to be used.
+file(MAKE_DIRECTORY ${LCOV_DATA_PATH_INIT})
+file(MAKE_DIRECTORY ${LCOV_DATA_PATH_CAPTURE})
+
+set(LCOV_REMOVE_PATTERNS "")
+
+# This function will merge lcov files to a single target file. Additional lcov
+# flags may be set with setting LCOV_EXTRA_FLAGS before calling this function.
+function (lcov_merge_files OUTFILE ...)
+	# Remove ${OUTFILE} from ${ARGV} and generate lcov parameters with files.
+	list(REMOVE_AT ARGV 0)
+
+	# Generate merged file.
+	string(REPLACE "${CMAKE_BINARY_DIR}/" "" FILE_REL "${OUTFILE}")
+	add_custom_command(OUTPUT "${OUTFILE}.raw"
+		COMMAND cat ${ARGV} > ${OUTFILE}.raw
+		DEPENDS ${ARGV}
+		COMMENT "Generating ${FILE_REL}"
+	)
+
+	add_custom_command(OUTPUT "${OUTFILE}"
+		COMMAND ${LCOV_BIN} --quiet -a ${OUTFILE}.raw --output-file ${OUTFILE}
+			--base-directory ${PROJECT_SOURCE_DIR} ${LCOV_EXTRA_FLAGS}
+		COMMAND ${LCOV_BIN} --quiet -r ${OUTFILE} ${LCOV_REMOVE_PATTERNS}
+			--output-file ${OUTFILE} ${LCOV_EXTRA_FLAGS}
+		DEPENDS ${OUTFILE}.raw
+		COMMENT "Post-processing ${FILE_REL}"
+	)
+endfunction ()
+
+
+
+
+# Add a new global target to generate initial coverage reports for all targets.
+# This target will be used to generate the global initial info file, which is
+# used to gather even empty report data.
+if (NOT TARGET lcov-capture-init)
+	add_custom_target(lcov-capture-init)
+	set(LCOV_CAPTURE_INIT_FILES "" CACHE INTERNAL "")
+endif (NOT TARGET lcov-capture-init)
+
+
+# This function will add initial capture of coverage data for target <TNAME>,
+# which is needed to get also data for objects, which were not loaded at
+# execution time. It will call geninfo for every source file of <TNAME> once and
+# store the info file in the same directory.
+function (lcov_capture_initial_tgt TNAME)
+	# We don't have to check, if the target has support for coverage, thus this
+	# will be checked by add_coverage_target in Findcoverage.cmake. Instead we
+	# have to determine which gcov binary to use.
+	get_target_property(TSOURCES ${TNAME} SOURCES)
+	set(SOURCES "")
+	set(TCOMPILER "")
+	foreach (FILE ${TSOURCES})
+		codecov_path_of_source(${FILE} FILE)
+		if (NOT "${FILE}" STREQUAL "")
+			codecov_lang_of_source(${FILE} LANG)
+			if (NOT "${LANG}" STREQUAL "")
+				list(APPEND SOURCES "${FILE}")
+				set(TCOMPILER ${CMAKE_${LANG}_COMPILER_ID})
+			endif ()
+		endif ()
+	endforeach ()
+
+	# If no gcov binary was found, coverage data can't be evaluated.
+	if (NOT GCOV_${TCOMPILER}_BIN)
+		message(WARNING "No coverage evaluation binary found for ${TCOMPILER}.")
+		return()
+	endif ()
+
+	set(GCOV_BIN "${GCOV_${TCOMPILER}_BIN}")
+	set(GCOV_ENV "${GCOV_${TCOMPILER}_ENV}")
+
+
+	set(TDIR ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/${TNAME}.dir)
+	set(GENINFO_FILES "")
+	foreach(FILE ${SOURCES})
+		# generate empty coverage files
+		set(OUTFILE "${TDIR}/${FILE}.info.init")
+		list(APPEND GENINFO_FILES ${OUTFILE})
+
+		add_custom_command(OUTPUT ${OUTFILE} COMMAND ${GCOV_ENV} ${GENINFO_BIN}
+				--quiet --base-directory ${PROJECT_SOURCE_DIR} --initial
+				--gcov-tool ${GCOV_BIN} --output-filename ${OUTFILE}
+				${GENINFO_EXTERN_FLAG} ${TDIR}/${FILE}.gcno
+			DEPENDS ${TNAME}
+			COMMENT "Capturing initial coverage data for ${FILE}"
+		)
+	endforeach()
+
+	# Concatenate all files generated by geninfo to a single file per target.
+	set(OUTFILE "${LCOV_DATA_PATH_INIT}/${TNAME}.info")
+	set(LCOV_EXTRA_FLAGS "--initial")
+	lcov_merge_files("${OUTFILE}" ${GENINFO_FILES})
+	add_custom_target(${TNAME}-capture-init ALL DEPENDS ${OUTFILE})
+
+	# add geninfo file generation to global lcov-geninfo target
+	add_dependencies(lcov-capture-init ${TNAME}-capture-init)
+	set(LCOV_CAPTURE_INIT_FILES "${LCOV_CAPTURE_INIT_FILES}"
+		"${OUTFILE}" CACHE INTERNAL ""
+	)
+endfunction (lcov_capture_initial_tgt)
+
+
+# This function will generate the global info file for all targets. It has to be
+# called after all other CMake functions in the root CMakeLists.txt file, to get
+# a full list of all targets that generate coverage data.
+function (lcov_capture_initial)
+	# Skip this function (and do not create the following targets), if there are
+	# no input files.
+	if ("${LCOV_CAPTURE_INIT_FILES}" STREQUAL "")
+		return()
+	endif ()
+
+	# Add a new target to merge the files of all targets.
+	set(OUTFILE "${LCOV_DATA_PATH_INIT}/all_targets.info")
+	lcov_merge_files("${OUTFILE}" ${LCOV_CAPTURE_INIT_FILES})
+	add_custom_target(lcov-geninfo-init ALL	DEPENDS ${OUTFILE}
+		lcov-capture-init
+	)
+endfunction (lcov_capture_initial)
+
+
+
+
+# Add a new global target to generate coverage reports for all targets. This
+# target will be used to generate the global info file.
+if (NOT TARGET lcov-capture)
+	add_custom_target(lcov-capture)
+	set(LCOV_CAPTURE_FILES "" CACHE INTERNAL "")
+endif (NOT TARGET lcov-capture)
+
+
+# This function will add capture of coverage data for target <TNAME>, which is
+# needed to get also data for objects, which were not loaded at execution time.
+# It will call geninfo for every source file of <TNAME> once and store the info
+# file in the same directory.
+function (lcov_capture_tgt TNAME)
+	# We don't have to check, if the target has support for coverage, thus this
+	# will be checked by add_coverage_target in Findcoverage.cmake. Instead we
+	# have to determine which gcov binary to use.
+	get_target_property(TSOURCES ${TNAME} SOURCES)
+	set(SOURCES "")
+	set(TCOMPILER "")
+	foreach (FILE ${TSOURCES})
+		codecov_path_of_source(${FILE} FILE)
+		if (NOT "${FILE}" STREQUAL "")
+			codecov_lang_of_source(${FILE} LANG)
+			if (NOT "${LANG}" STREQUAL "")
+				list(APPEND SOURCES "${FILE}")
+				set(TCOMPILER ${CMAKE_${LANG}_COMPILER_ID})
+			endif ()
+		endif ()
+	endforeach ()
+
+	# If no gcov binary was found, coverage data can't be evaluated.
+	if (NOT GCOV_${TCOMPILER}_BIN)
+		message(WARNING "No coverage evaluation binary found for ${TCOMPILER}.")
+		return()
+	endif ()
+
+	set(GCOV_BIN "${GCOV_${TCOMPILER}_BIN}")
+	set(GCOV_ENV "${GCOV_${TCOMPILER}_ENV}")
+
+
+	set(TDIR ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/${TNAME}.dir)
+	set(GENINFO_FILES "")
+	foreach(FILE ${SOURCES})
+		# Generate coverage files. If no .gcda file was generated during
+		# execution, the empty coverage file will be used instead.
+		set(OUTFILE "${TDIR}/${FILE}.info")
+		list(APPEND GENINFO_FILES ${OUTFILE})
+
+		add_custom_command(OUTPUT ${OUTFILE}
+			COMMAND test -f "${TDIR}/${FILE}.gcda"
+				&& ${GCOV_ENV} ${GENINFO_BIN} --quiet --base-directory
+					${PROJECT_SOURCE_DIR} --gcov-tool ${GCOV_BIN}
+					--output-filename ${OUTFILE} ${GENINFO_EXTERN_FLAG}
+					${TDIR}/${FILE}.gcda
+				|| cp ${OUTFILE}.init ${OUTFILE}
+			DEPENDS ${TNAME} ${TNAME}-capture-init
+			COMMENT "Capturing coverage data for ${FILE}"
+		)
+	endforeach()
+
+	# Concatenate all files generated by geninfo to a single file per target.
+	set(OUTFILE "${LCOV_DATA_PATH_CAPTURE}/${TNAME}.info")
+	lcov_merge_files("${OUTFILE}" ${GENINFO_FILES})
+	add_custom_target(${TNAME}-geninfo DEPENDS ${OUTFILE})
+
+	# add geninfo file generation to global lcov-capture target
+	add_dependencies(lcov-capture ${TNAME}-geninfo)
+	set(LCOV_CAPTURE_FILES "${LCOV_CAPTURE_FILES}" "${OUTFILE}" CACHE INTERNAL
+		""
+	)
+
+	# Add target for generating html output for this target only.
+	file(MAKE_DIRECTORY ${LCOV_HTML_PATH}/${TNAME})
+	add_custom_target(${TNAME}-genhtml
+		COMMAND ${GENHTML_BIN} --quiet --sort --prefix ${PROJECT_SOURCE_DIR}
+			--baseline-file ${LCOV_DATA_PATH_INIT}/${TNAME}.info
+			--output-directory ${LCOV_HTML_PATH}/${TNAME}
+			--title "${CMAKE_PROJECT_NAME} - target ${TNAME}"
+			${GENHTML_CPPFILT_FLAG} ${OUTFILE}
+		DEPENDS ${TNAME}-geninfo ${TNAME}-capture-init
+	)
+endfunction (lcov_capture_tgt)
+
+
+# This function will generate the global info file for all targets. It has to be
+# called after all other CMake functions in the root CMakeLists.txt file, to get
+# a full list of all targets that generate coverage data.
+function (lcov_capture)
+	# Skip this function (and do not create the following targets), if there are
+	# no input files.
+	if ("${LCOV_CAPTURE_FILES}" STREQUAL "")
+		return()
+	endif ()
+
+	# Add a new target to merge the files of all targets.
+	set(OUTFILE "${LCOV_DATA_PATH_CAPTURE}/all_targets.info")
+	lcov_merge_files("${OUTFILE}" ${LCOV_CAPTURE_FILES})
+	add_custom_target(lcov-geninfo DEPENDS ${OUTFILE} lcov-capture)
+
+	# Add a new global target for all lcov targets. This target could be used to
+	# generate the lcov html output for the whole project instead of calling
+	# <TARGET>-geninfo and <TARGET>-genhtml for each target. It will also be
+	# used to generate a html site for all project data together instead of one
+	# for each target.
+	if (NOT TARGET lcov)
+		file(MAKE_DIRECTORY ${LCOV_HTML_PATH}/all_targets)
+		add_custom_target(lcov
+			COMMAND ${GENHTML_BIN} --quiet --sort
+				--baseline-file ${LCOV_DATA_PATH_INIT}/all_targets.info
+				--output-directory ${LCOV_HTML_PATH}/all_targets
+				--title "${CMAKE_PROJECT_NAME}" --prefix "${PROJECT_SOURCE_DIR}"
+				${GENHTML_CPPFILT_FLAG} ${OUTFILE}
+			DEPENDS lcov-geninfo-init lcov-geninfo
+		)
+	endif ()
+endfunction (lcov_capture)
+
+
+
+
+# Add a new global target to generate the lcov html report for the whole project
+# instead of calling <TARGET>-genhtml for each target (to create an own report
+# for each target). Instead of the lcov target it does not require geninfo for
+# all targets, so you have to call <TARGET>-geninfo to generate the info files
+# the targets you'd like to have in your report or lcov-geninfo for generating
+# info files for all targets before calling lcov-genhtml.
+file(MAKE_DIRECTORY ${LCOV_HTML_PATH}/selected_targets)
+if (NOT TARGET lcov-genhtml)
+	add_custom_target(lcov-genhtml
+		COMMAND ${GENHTML_BIN}
+			--quiet
+			--output-directory ${LCOV_HTML_PATH}/selected_targets
+			--title \"${CMAKE_PROJECT_NAME} - targets  `find
+				${LCOV_DATA_PATH_CAPTURE} -name \"*.info\" ! -name
+				\"all_targets.info\" -exec basename {} .info \\\;`\"
+			--prefix ${PROJECT_SOURCE_DIR}
+			--sort
+			${GENHTML_CPPFILT_FLAG}
+			`find ${LCOV_DATA_PATH_CAPTURE} -name \"*.info\" ! -name
+				\"all_targets.info\"`
+	)
+endif (NOT TARGET lcov-genhtml)

externals/catch/CMake/Findcodecov.cmake

@@ -0,0 +1,258 @@
+# This file is part of CMake-codecov.
+#
+# Copyright (c)
+#   2015-2017 RWTH Aachen University, Federal Republic of Germany
+#
+# See the LICENSE file in the package base directory for details
+#
+# Written by Alexander Haase, alexander.haase@rwth-aachen.de
+#
+
+
+# Add an option to choose, if coverage should be enabled or not. If enabled
+# marked targets will be build with coverage support and appropriate targets
+# will be added. If disabled coverage will be ignored for *ALL* targets.
+option(ENABLE_COVERAGE "Enable coverage build." OFF)
+
+set(COVERAGE_FLAG_CANDIDATES
+	# gcc and clang
+	"-O0 -g -fprofile-arcs -ftest-coverage"
+
+	# gcc and clang fallback
+	"-O0 -g --coverage"
+)
+
+
+# Add coverage support for target ${TNAME} and register target for coverage
+# evaluation. If coverage is disabled or not supported, this function will
+# simply do nothing.
+#
+# Note: This function is only a wrapper to define this function always, even if
+#   coverage is not supported by the compiler or disabled. This function must
+#   be defined here, because the module will be exited, if there is no coverage
+#   support by the compiler or it is disabled by the user.
+function (add_coverage TNAME)
+	# only add coverage for target, if coverage is support and enabled.
+	if (ENABLE_COVERAGE)
+		foreach (TNAME ${ARGV})
+			add_coverage_target(${TNAME})
+		endforeach ()
+	endif ()
+endfunction (add_coverage)
+
+
+# Add global target to gather coverage information after all targets have been
+# added. Other evaluation functions could be added here, after checks for the
+# specific module have been passed.
+#
+# Note: This function is only a wrapper to define this function always, even if
+#   coverage is not supported by the compiler or disabled. This function must
+#   be defined here, because the module will be exited, if there is no coverage
+#   support by the compiler or it is disabled by the user.
+function (coverage_evaluate)
+	# add lcov evaluation
+	if (LCOV_FOUND)
+		lcov_capture_initial()
+		lcov_capture()
+	endif (LCOV_FOUND)
+endfunction ()
+
+
+# Exit this module, if coverage is disabled. add_coverage is defined before this
+# return, so this module can be exited now safely without breaking any build-
+# scripts.
+if (NOT ENABLE_COVERAGE)
+	return()
+endif ()
+
+
+
+
+# Find the reuired flags foreach language.
+set(CMAKE_REQUIRED_QUIET_SAVE ${CMAKE_REQUIRED_QUIET})
+set(CMAKE_REQUIRED_QUIET ${codecov_FIND_QUIETLY})
+
+get_property(ENABLED_LANGUAGES GLOBAL PROPERTY ENABLED_LANGUAGES)
+foreach (LANG ${ENABLED_LANGUAGES})
+	# Coverage flags are not dependent on language, but the used compiler. So
+	# instead of searching flags foreach language, search flags foreach compiler
+	# used.
+	set(COMPILER ${CMAKE_${LANG}_COMPILER_ID})
+	if (NOT COVERAGE_${COMPILER}_FLAGS)
+		foreach (FLAG ${COVERAGE_FLAG_CANDIDATES})
+			if(NOT CMAKE_REQUIRED_QUIET)
+				message(STATUS "Try ${COMPILER} code coverage flag = [${FLAG}]")
+			endif()
+
+			set(CMAKE_REQUIRED_FLAGS "${FLAG}")
+			unset(COVERAGE_FLAG_DETECTED CACHE)
+
+			if (${LANG} STREQUAL "C")
+				include(CheckCCompilerFlag)
+				check_c_compiler_flag("${FLAG}" COVERAGE_FLAG_DETECTED)
+
+			elseif (${LANG} STREQUAL "CXX")
+				include(CheckCXXCompilerFlag)
+				check_cxx_compiler_flag("${FLAG}" COVERAGE_FLAG_DETECTED)
+
+			elseif (${LANG} STREQUAL "Fortran")
+				# CheckFortranCompilerFlag was introduced in CMake 3.x. To be
+				# compatible with older Cmake versions, we will check if this
+				# module is present before we use it. Otherwise we will define
+				# Fortran coverage support as not available.
+				include(CheckFortranCompilerFlag OPTIONAL
+					RESULT_VARIABLE INCLUDED)
+				if (INCLUDED)
+					check_fortran_compiler_flag("${FLAG}"
+						COVERAGE_FLAG_DETECTED)
+				elseif (NOT CMAKE_REQUIRED_QUIET)
+					message("-- Performing Test COVERAGE_FLAG_DETECTED")
+					message("-- Performing Test COVERAGE_FLAG_DETECTED - Failed"
+						" (Check not supported)")
+				endif ()
+			endif()
+
+			if (COVERAGE_FLAG_DETECTED)
+				set(COVERAGE_${COMPILER}_FLAGS "${FLAG}"
+					CACHE STRING "${COMPILER} flags for code coverage.")
+				mark_as_advanced(COVERAGE_${COMPILER}_FLAGS)
+				break()
+			else ()
+				message(WARNING "Code coverage is not available for ${COMPILER}"
+				        " compiler. Targets using this compiler will be "
+				        "compiled without it.")
+			endif ()
+		endforeach ()
+	endif ()
+endforeach ()
+
+set(CMAKE_REQUIRED_QUIET ${CMAKE_REQUIRED_QUIET_SAVE})
+
+
+
+
+# Helper function to get the language of a source file.
+function (codecov_lang_of_source FILE RETURN_VAR)
+	get_filename_component(FILE_EXT "${FILE}" EXT)
+	string(TOLOWER "${FILE_EXT}" FILE_EXT)
+	string(SUBSTRING "${FILE_EXT}" 1 -1 FILE_EXT)
+
+	get_property(ENABLED_LANGUAGES GLOBAL PROPERTY ENABLED_LANGUAGES)
+	foreach (LANG ${ENABLED_LANGUAGES})
+		list(FIND CMAKE_${LANG}_SOURCE_FILE_EXTENSIONS "${FILE_EXT}" TEMP)
+		if (NOT ${TEMP} EQUAL -1)
+			set(${RETURN_VAR} "${LANG}" PARENT_SCOPE)
+			return()
+		endif ()
+	endforeach()
+
+	set(${RETURN_VAR} "" PARENT_SCOPE)
+endfunction ()
+
+
+# Helper function to get the relative path of the source file destination path.
+# This path is needed by FindGcov and FindLcov cmake files to locate the
+# captured data.
+function (codecov_path_of_source FILE RETURN_VAR)
+	string(REGEX MATCH "TARGET_OBJECTS:([^ >]+)" _source ${FILE})
+
+	# If expression was found, SOURCEFILE is a generator-expression for an
+	# object library. Currently we found no way to call this function automatic
+	# for the referenced target, so it must be called in the directoryso of the
+	# object library definition.
+	if (NOT "${_source}" STREQUAL "")
+		set(${RETURN_VAR} "" PARENT_SCOPE)
+		return()
+	endif ()
+
+
+	string(REPLACE "${CMAKE_CURRENT_BINARY_DIR}/" "" FILE "${FILE}")
+	if(IS_ABSOLUTE ${FILE})
+		file(RELATIVE_PATH FILE ${CMAKE_CURRENT_SOURCE_DIR} ${FILE})
+	endif()
+
+	# get the right path for file
+	string(REPLACE ".." "__" PATH "${FILE}")
+
+	set(${RETURN_VAR} "${PATH}" PARENT_SCOPE)
+endfunction()
+
+
+
+
+# Add coverage support for target ${TNAME} and register target for coverage
+# evaluation.
+function(add_coverage_target TNAME)
+	# Check if all sources for target use the same compiler. If a target uses
+	# e.g. C and Fortran mixed and uses different compilers (e.g. clang and
+	# gfortran) this can trigger huge problems, because different compilers may
+	# use different implementations for code coverage.
+	get_target_property(TSOURCES ${TNAME} SOURCES)
+	set(TARGET_COMPILER "")
+	set(ADDITIONAL_FILES "")
+	foreach (FILE ${TSOURCES})
+		# If expression was found, FILE is a generator-expression for an object
+		# library. Object libraries will be ignored.
+		string(REGEX MATCH "TARGET_OBJECTS:([^ >]+)" _file ${FILE})
+		if ("${_file}" STREQUAL "")
+			codecov_lang_of_source(${FILE} LANG)
+			if (LANG)
+				list(APPEND TARGET_COMPILER ${CMAKE_${LANG}_COMPILER_ID})
+
+				list(APPEND ADDITIONAL_FILES "${FILE}.gcno")
+				list(APPEND ADDITIONAL_FILES "${FILE}.gcda")
+			endif ()
+		endif ()
+	endforeach ()
+
+	list(REMOVE_DUPLICATES TARGET_COMPILER)
+	list(LENGTH TARGET_COMPILER NUM_COMPILERS)
+
+	if (NUM_COMPILERS GREATER 1)
+		message(WARNING "Can't use code coverage for target ${TNAME}, because "
+		        "it will be compiled by incompatible compilers. Target will be "
+		        "compiled without code coverage.")
+		return()
+
+	elseif (NUM_COMPILERS EQUAL 0)
+		message(WARNING "Can't use code coverage for target ${TNAME}, because "
+		        "it uses an unknown compiler. Target will be compiled without "
+		        "code coverage.")
+		return()
+
+	elseif (NOT DEFINED "COVERAGE_${TARGET_COMPILER}_FLAGS")
+		# A warning has been printed before, so just return if flags for this
+		# compiler aren't available.
+		return()
+	endif()
+
+
+	# enable coverage for target
+	set_property(TARGET ${TNAME} APPEND_STRING
+		PROPERTY COMPILE_FLAGS " ${COVERAGE_${TARGET_COMPILER}_FLAGS}")
+	set_property(TARGET ${TNAME} APPEND_STRING
+		PROPERTY LINK_FLAGS " ${COVERAGE_${TARGET_COMPILER}_FLAGS}")
+
+
+	# Add gcov files generated by compiler to clean target.
+	set(CLEAN_FILES "")
+	foreach (FILE ${ADDITIONAL_FILES})
+		codecov_path_of_source(${FILE} FILE)
+		list(APPEND CLEAN_FILES "CMakeFiles/${TNAME}.dir/${FILE}")
+	endforeach()
+
+	set_directory_properties(PROPERTIES ADDITIONAL_MAKE_CLEAN_FILES
+		"${CLEAN_FILES}")
+
+
+	add_gcov_target(${TNAME})
+	add_lcov_target(${TNAME})
+endfunction(add_coverage_target)
+
+
+
+
+# Include modules for parsing the collected data and output it in a readable
+# format (like gcov and lcov).
+find_package(Gcov)
+find_package(Lcov)

externals/catch/CMake/catch2-with-main.pc.in

@@ -0,0 +1,10 @@
+includedir=@CMAKE_INSTALL_FULL_INCLUDEDIR@
+libdir=@CMAKE_INSTALL_FULL_LIBDIR@
+pkg_version=@Catch2_VERSION@
+
+Name: Catch2-With-Main
+Description: A modern, C++-native test framework for C++14 and above (links in default main)
+Version: ${pkg_version}
+Requires: catch2 = ${pkg_version}
+Cflags: -I${includedir}
+Libs: -L${libdir} -lCatch2Main

externals/catch/CMake/catch2.pc.in

@@ -0,0 +1,11 @@
+prefix=@CMAKE_INSTALL_PREFIX@
+exec_prefix=${prefix}
+includedir=@CMAKE_INSTALL_FULL_INCLUDEDIR@
+libdir=@CMAKE_INSTALL_FULL_LIBDIR@
+
+Name: Catch2
+Description: A modern, C++-native, test framework for C++14 and above
+URL: https://github.com/catchorg/Catch2
+Version: @Catch2_VERSION@
+Cflags: -I${includedir}
+Libs: -L${libdir} -lCatch2

externals/catch/CMake/llvm-cov-wrapper

@@ -0,0 +1,56 @@
+#!/bin/sh
+
+# This file is part of CMake-codecov.
+#
+# Copyright (c)
+#   2015-2017 RWTH Aachen University, Federal Republic of Germany
+#
+# See the LICENSE file in the package base directory for details
+#
+# Written by Alexander Haase, alexander.haase@rwth-aachen.de
+#
+
+if [ -z "$LLVM_COV_BIN" ]
+then
+	echo "LLVM_COV_BIN not set!" >& 2
+	exit 1
+fi
+
+
+# Get LLVM version to find out.
+LLVM_VERSION=$($LLVM_COV_BIN -version | grep -i "LLVM version" \
+	| sed "s/^\([A-Za-z ]*\)\([0-9]\).\([0-9]\).*$/\2.\3/g")
+
+if [ "$1" = "-v" ]
+then
+	echo "llvm-cov-wrapper $LLVM_VERSION"
+	exit 0
+fi
+
+
+if [ -n "$LLVM_VERSION" ]
+then
+	MAJOR=$(echo $LLVM_VERSION | cut -d'.' -f1)
+	MINOR=$(echo $LLVM_VERSION | cut -d'.' -f2)
+
+	if [ $MAJOR -eq 3 ] && [ $MINOR -le 4 ]
+	then
+		if [ -f "$1" ]
+		then
+			filename=$(basename "$1")
+			extension="${filename##*.}"
+
+			case "$extension" in
+				"gcno") exec $LLVM_COV_BIN --gcno="$1" ;;
+				"gcda") exec $LLVM_COV_BIN --gcda="$1" ;;
+			esac
+		fi
+	fi
+
+	if [ $MAJOR -eq 3 ] && [ $MINOR -le 5 ]
+	then
+		exec $LLVM_COV_BIN $@
+	fi
+fi
+
+exec $LLVM_COV_BIN gcov $@

externals/catch/CMakeLists.txt

@@ -0,0 +1,199 @@
+cmake_minimum_required(VERSION 3.10)
+
+# detect if Catch is being bundled,
+# disable testsuite in that case
+if(NOT DEFINED PROJECT_NAME)
+  set(NOT_SUBPROJECT ON)
+else()
+  set(NOT_SUBPROJECT OFF)
+endif()
+
+option(CATCH_INSTALL_DOCS "Install documentation alongside library" ON)
+option(CATCH_INSTALL_EXTRAS "Install extras (CMake scripts, debugger helpers) alongside library" ON)
+option(CATCH_DEVELOPMENT_BUILD "Build tests, enable warnings, enable Werror, etc" OFF)
+
+include(CMakeDependentOption)
+cmake_dependent_option(CATCH_BUILD_TESTING "Build the SelfTest project" ON "CATCH_DEVELOPMENT_BUILD" OFF)
+cmake_dependent_option(CATCH_BUILD_EXAMPLES "Build code examples" OFF "CATCH_DEVELOPMENT_BUILD" OFF)
+cmake_dependent_option(CATCH_BUILD_EXTRA_TESTS "Build extra tests" OFF "CATCH_DEVELOPMENT_BUILD" OFF)
+cmake_dependent_option(CATCH_BUILD_FUZZERS "Build fuzzers" OFF "CATCH_DEVELOPMENT_BUILD" OFF)
+cmake_dependent_option(CATCH_ENABLE_COVERAGE "Generate coverage for codecov.io" OFF "CATCH_DEVELOPMENT_BUILD" OFF)
+cmake_dependent_option(CATCH_ENABLE_WERROR "Enables Werror during build" ON "CATCH_DEVELOPMENT_BUILD" OFF)
+cmake_dependent_option(CATCH_BUILD_SURROGATES "Enable generating and building surrogate TUs for the main headers" OFF "CATCH_DEVELOPMENT_BUILD" OFF)
+cmake_dependent_option(CATCH_ENABLE_CONFIGURE_TESTS "Enable CMake configuration tests. WARNING: VERY EXPENSIVE" OFF "CATCH_DEVELOPMENT_BUILD" OFF)
+
+
+# Catch2's build breaks if done in-tree. You probably should not build
+# things in tree anyway, but we can allow projects that include Catch2
+# as a subproject to build in-tree as long as it is not in our tree.
+if (CMAKE_BINARY_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
+    message(FATAL_ERROR "Building in-source is not supported! Create a build dir and remove ${CMAKE_SOURCE_DIR}/CMakeCache.txt")
+endif()
+
+project(Catch2
+  VERSION 3.2.1 # CML version placeholder, don't delete
+  LANGUAGES CXX
+  # HOMEPAGE_URL is not supported until CMake version 3.12, which
+  # we do not target yet.
+  # HOMEPAGE_URL "https://github.com/catchorg/Catch2"
+  DESCRIPTION "A modern, C++-native, unit test framework."
+)
+
+
+# Provide path for scripts. We first add path to the scripts we don't use,
+# but projects including us might, and set the path up to parent scope.
+# Then we also add path that we use to configure the project, but is of
+# no use to top level projects.
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/extras")
+if (NOT NOT_SUBPROJECT)
+  set(CMAKE_MODULE_PATH "${CMAKE_MODULE_PATH}" PARENT_SCOPE)
+endif()
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/CMake")
+
+include(GNUInstallDirs)
+include(CMakePackageConfigHelpers)
+include(CatchConfigOptions)
+if(CATCH_DEVELOPMENT_BUILD)
+  include(CTest)
+endif()
+
+# This variable is used in some subdirectories, so we need it here, rather
+# than later in the install block
+set(CATCH_CMAKE_CONFIG_DESTINATION "${CMAKE_INSTALL_LIBDIR}/cmake/Catch2")
+
+# We have some Windows builds that test `wmain` entry point,
+# and we need this change to be present in all binaries that
+# are built during these tests, so this is required here, before
+# the subdirectories are added.
+if(CATCH_TEST_USE_WMAIN)
+    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} /ENTRY:wmainCRTStartup")
+endif()
+
+
+# Basic paths
+set(CATCH_DIR ${CMAKE_CURRENT_SOURCE_DIR})
+set(SOURCES_DIR ${CATCH_DIR}/src/catch2)
+set(SELF_TEST_DIR ${CATCH_DIR}/tests/SelfTest)
+set(BENCHMARK_DIR ${CATCH_DIR}/tests/Benchmark)
+set(EXAMPLES_DIR ${CATCH_DIR}/examples)
+
+# We need to bring-in the variables defined there to this scope
+add_subdirectory(src)
+
+# Build tests only if requested
+if (BUILD_TESTING AND CATCH_BUILD_TESTING AND NOT_SUBPROJECT)
+    find_package(PythonInterp 3 REQUIRED)
+    if (NOT PYTHONINTERP_FOUND)
+        message(FATAL_ERROR "Python not found, but required for tests")
+    endif()
+    add_subdirectory(tests)
+endif()
+
+if(CATCH_BUILD_EXAMPLES)
+    add_subdirectory(examples)
+endif()
+
+if(CATCH_BUILD_EXTRA_TESTS)
+    add_subdirectory(tests/ExtraTests)
+endif()
+
+if(CATCH_BUILD_FUZZERS)
+    add_subdirectory(fuzzing)
+endif()
+
+if (CATCH_DEVELOPMENT_BUILD)
+    add_warnings_to_targets("${CATCH_WARNING_TARGETS}")
+endif()
+
+# Only perform the installation steps when Catch is not being used as
+# a subproject via `add_subdirectory`, or the destinations will break,
+# see https://github.com/catchorg/Catch2/issues/1373
+if (NOT_SUBPROJECT)
+    configure_package_config_file(
+        ${CMAKE_CURRENT_LIST_DIR}/CMake/Catch2Config.cmake.in
+        ${CMAKE_CURRENT_BINARY_DIR}/Catch2Config.cmake
+        INSTALL_DESTINATION
+          ${CATCH_CMAKE_CONFIG_DESTINATION}
+    )
+
+    write_basic_package_version_file(
+      "${CMAKE_CURRENT_BINARY_DIR}/Catch2ConfigVersion.cmake"
+      COMPATIBILITY
+        SameMajorVersion
+    )
+
+    install(
+      FILES
+        "${CMAKE_CURRENT_BINARY_DIR}/Catch2Config.cmake"
+        "${CMAKE_CURRENT_BINARY_DIR}/Catch2ConfigVersion.cmake"
+      DESTINATION
+        ${CATCH_CMAKE_CONFIG_DESTINATION}
+    )
+
+    # Install documentation
+    if(CATCH_INSTALL_DOCS)
+      install(
+        DIRECTORY
+          docs/
+        DESTINATION
+          "${CMAKE_INSTALL_DOCDIR}"
+        PATTERN "doxygen" EXCLUDE
+      )
+    endif()
+
+    if(CATCH_INSTALL_EXTRAS)
+        # Install CMake scripts
+        install(
+          FILES
+            "extras/ParseAndAddCatchTests.cmake"
+            "extras/Catch.cmake"
+            "extras/CatchAddTests.cmake"
+          DESTINATION
+            ${CATCH_CMAKE_CONFIG_DESTINATION}
+        )
+    
+        # Install debugger helpers
+        install(
+          FILES
+            "extras/gdbinit"
+            "extras/lldbinit"
+          DESTINATION
+            ${CMAKE_INSTALL_DATAROOTDIR}/Catch2
+        )
+    endif()
+
+    ## Provide some pkg-config integration
+    set(PKGCONFIG_INSTALL_DIR
+        "${CMAKE_INSTALL_DATAROOTDIR}/pkgconfig"
+        CACHE PATH "Path where catch2.pc is installed"
+    )
+    configure_file(
+      ${CMAKE_CURRENT_SOURCE_DIR}/CMake/catch2.pc.in
+      ${CMAKE_CURRENT_BINARY_DIR}/catch2.pc
+      @ONLY
+    )
+    configure_file(
+      ${CMAKE_CURRENT_SOURCE_DIR}/CMake/catch2-with-main.pc.in
+      ${CMAKE_CURRENT_BINARY_DIR}/catch2-with-main.pc
+      @ONLY
+    )
+    install(
+      FILES
+        "${CMAKE_CURRENT_BINARY_DIR}/catch2.pc"
+        "${CMAKE_CURRENT_BINARY_DIR}/catch2-with-main.pc"
+      DESTINATION
+        ${PKGCONFIG_INSTALL_DIR}
+    )
+
+    # CPack/CMake started taking the package version from project version 3.12
+    # So we need to set the version manually for older CMake versions
+    if(${CMAKE_VERSION} VERSION_LESS "3.12.0")
+        set(CPACK_PACKAGE_VERSION ${PROJECT_VERSION})
+    endif()
+
+    set(CPACK_PACKAGE_CONTACT "https://github.com/catchorg/Catch2/")
+
+
+    include( CPack )
+
+endif(NOT_SUBPROJECT)

externals/catch/CMakePresets.json

@@ -0,0 +1,25 @@
+{
+    "version": 3,
+    "configurePresets": [
+        {
+            "name": "basic-tests",
+            "displayName": "Basic development build",
+            "description": "Enables development build with basic tests that are cheap to build and run",
+            "cacheVariables": {
+                "CATCH_DEVELOPMENT_BUILD": "ON"
+            }
+        },
+        {
+            "name": "all-tests",
+            "inherits": "basic-tests",
+            "displayName": "Full development build",
+            "description": "Enables development build with examples and ALL tests",
+            "cacheVariables": {
+                "CATCH_BUILD_EXAMPLES": "ON",
+                "CATCH_BUILD_EXTRA_TESTS": "ON",
+                "CATCH_BUILD_SURROGATES": "ON",
+                "CATCH_ENABLE_CONFIGURE_TESTS": "ON"
+            }
+        }
+    ]   
+}

externals/catch/CODE_OF_CONDUCT.md

@@ -0,0 +1,46 @@
+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+In the interest of fostering an open and welcoming environment, we as contributors and maintainers pledge to making participation in our project and our community a harassment-free experience for everyone, regardless of age, body size, disability, ethnicity, gender identity and expression, level of experience, nationality, personal appearance, race, religion, or sexual identity and orientation.
+
+## Our Standards
+
+Examples of behavior that contributes to creating a positive environment include:
+
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
+* Showing empathy towards other community members
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery and unwelcome sexual attention or advances
+* Trolling, insulting/derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or electronic address, without explicit permission
+* Other conduct which could reasonably be considered inappropriate in a professional setting
+
+## Our Responsibilities
+
+Project maintainers are responsible for clarifying the standards of acceptable behavior and are expected to take appropriate and fair corrective action in response to any instances of unacceptable behavior.
+
+Project maintainers have the right and responsibility to remove, edit, or reject comments, commits, code, wiki edits, issues, and other contributions that are not aligned to this Code of Conduct, or to ban temporarily or permanently any contributor for other behaviors that they deem inappropriate, threatening, offensive, or harmful.
+
+## Scope
+
+This Code of Conduct applies both within project spaces and in public spaces when an individual is representing the project or its community. Examples of representing a project or community include using an official project e-mail address, posting via an official social media account, or acting as an appointed representative at an online or offline event. Representation of a project may be further defined and clarified by project maintainers.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be reported by contacting the project team at github@philnash.me. The project team will review and investigate all complaints, and will respond in a way that it deems appropriate to the circumstances. The project team is obligated to maintain confidentiality with regard to the reporter of an incident. Further details of specific enforcement policies may be posted separately.
+
+Project maintainers who do not follow or enforce the Code of Conduct in good faith may face temporary or permanent repercussions as determined by other members of the project's leadership.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4, available at [http://contributor-covenant.org/version/1/4][version]
+
+[homepage]: http://contributor-covenant.org
+[version]: http://contributor-covenant.org/version/1/4/

externals/catch/LICENSE.txt

@@ -0,0 +1,23 @@
+Boost Software License - Version 1.0 - August 17th, 2003
+
+Permission is hereby granted, free of charge, to any person or organization
+obtaining a copy of the software and accompanying documentation covered by
+this license (the "Software") to use, reproduce, display, distribute,
+execute, and transmit the Software, and to prepare derivative works of the
+Software, and to permit third-parties to whom the Software is furnished to
+do so, all subject to the following:
+
+The copyright notices in the Software and this entire statement, including
+the above license grant, this restriction and the following disclaimer,
+must be included in all copies of the Software, in whole or in part, and
+all derivative works of the Software, unless such copies or derivative
+works are solely in the form of machine-executable object code generated by
+a source language processor.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.

externals/catch/README.md

@@ -0,0 +1,99 @@
+<a id="top"></a>
+![Catch2 logo](data/artwork/catch2-logo-small-with-background.png)
+
+[![Github Releases](https://img.shields.io/github/release/catchorg/catch2.svg)](https://github.com/catchorg/catch2/releases)
+[![Linux build status](https://github.com/catchorg/Catch2/actions/workflows/linux-simple-builds.yml/badge.svg)](https://github.com/catchorg/Catch2/actions/workflows/linux-simple-builds.yml)
+[![Linux build status](https://github.com/catchorg/Catch2/actions/workflows/linux-other-builds.yml/badge.svg)](https://github.com/catchorg/Catch2/actions/workflows/linux-other-builds.yml)
+[![MacOS build status](https://github.com/catchorg/Catch2/actions/workflows/mac-builds.yml/badge.svg)](https://github.com/catchorg/Catch2/actions/workflows/mac-builds.yml)
+[![Build Status](https://ci.appveyor.com/api/projects/status/github/catchorg/Catch2?svg=true&branch=devel)](https://ci.appveyor.com/project/catchorg/catch2)
+[![Code Coverage](https://codecov.io/gh/catchorg/Catch2/branch/devel/graph/badge.svg)](https://codecov.io/gh/catchorg/Catch2)
+[![Try online](https://img.shields.io/badge/try-online-blue.svg)](https://godbolt.org/z/EdoY15q9G)
+[![Join the chat in Discord: https://discord.gg/4CWS9zD](https://img.shields.io/badge/Discord-Chat!-brightgreen.svg)](https://discord.gg/4CWS9zD)
+
+
+## What is Catch2?
+
+Catch2 is mainly a unit testing framework for C++, but it also
+provides basic micro-benchmarking features, and simple BDD macros.
+
+Catch2's main advantage is that using it is both simple and natural.
+Test names do not have to be valid identifiers, assertions look like
+normal C++ boolean expressions, and sections provide a nice and local way
+to share set-up and tear-down code in tests.
+
+**Example unit test**
+```cpp
+#include <catch2/catch_test_macros.hpp>
+
+#include <cstdint>
+
+uint32_t factorial( uint32_t number ) {
+    return number <= 1 ? number : factorial(number-1) * number;
+}
+
+TEST_CASE( "Factorials are computed", "[factorial]" ) {
+    REQUIRE( factorial( 1) == 1 );
+    REQUIRE( factorial( 2) == 2 );
+    REQUIRE( factorial( 3) == 6 );
+    REQUIRE( factorial(10) == 3'628'800 );
+}
+```
+
+**Example microbenchmark**
+```cpp
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/benchmark/catch_benchmark.hpp>
+
+#include <cstdint>
+
+uint64_t fibonacci(uint64_t number) {
+    return number < 2 ? 1 : fibonacci(number - 1) + fibonacci(number - 2);
+}
+
+TEST_CASE("Benchmark Fibonacci", "[!benchmark]") {
+    REQUIRE(Fibonacci(5) == 5);
+
+    REQUIRE(Fibonacci(20) == 6'765);
+    BENCHMARK("Fibonacci 20") {
+        return Fibonacci(20);
+    };
+
+    REQUIRE(Fibonacci(25) == 75'025);
+    BENCHMARK("Fibonacci 25") {
+        return Fibonacci(25);
+    };
+}
+```
+
+## Catch2 v3 has been released!
+
+You are on the `devel` branch, where the v3 version is being developed.
+v3 brings a bunch of significant changes, the big one being that Catch2
+is no longer a single-header library. Catch2 now behaves as a normal
+library, with multiple headers and separately compiled implementation.
+
+The documentation is slowly being updated to take these changes into
+account, but this work is currently still ongoing.
+
+For migrating from the v2 releases to v3, you should look at [our
+documentation](docs/migrate-v2-to-v3.md#top). It provides a simple
+guidelines on getting started, and collects most common migration
+problems.
+
+For the previous major version of Catch2 [look into the `v2.x` branch
+here on GitHub](https://github.com/catchorg/Catch2/tree/v2.x).
+
+
+## How to use it
+This documentation comprises these three parts:
+
+* [Why do we need yet another C++ Test Framework?](docs/why-catch.md#top)
+* [Tutorial](docs/tutorial.md#top) - getting started
+* [Reference section](docs/Readme.md#top) - all the details
+
+
+## More
+* Issues and bugs can be raised on the [Issue tracker on GitHub](https://github.com/catchorg/Catch2/issues)
+* For discussion or questions please use [our Discord](https://discord.gg/4CWS9zD)
+* See who else is using Catch2 in [Open Source Software](docs/opensource-users.md#top)
+or [commercially](docs/commercial-users.md#top).

externals/catch/SECURITY.md

@@ -0,0 +1,19 @@
+# Security Policy
+
+## Supported Versions
+
+* Versions 1.x (branch Catch1.x) are no longer supported.
+* Versions 2.x (branch v2.x) are currently supported.
+* `devel` branch serves for stable-ish development and is supported,
+  but branches `devel-*` are considered short lived and are not supported separately.
+
+
+## Reporting a Vulnerability
+
+Due to its nature as a _unit_ test framework, Catch2 shouldn't interact
+with untrusted inputs and there shouldn't be many security vulnerabilities
+in it.
+
+However, if you find one you send email to martin <dot> horenovsky <at>
+gmail <dot> com. If you want to encrypt the email, my pgp key is
+`E29C 46F3 B8A7 5028 6079 3B7D ECC9 C20E 314B 2360`.

externals/catch/WORKSPACE.bazel

@@ -0,0 +1,15 @@
+workspace(name = "catch2")
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+http_archive(
+    name = "bazel_skylib",
+    urls = [
+        "https://mirror.bazel.build/github.com/bazelbuild/bazel-skylib/releases/download/1.3.0/bazel-skylib-1.3.0.tar.gz",
+        "https://github.com/bazelbuild/bazel-skylib/releases/download/1.3.0/bazel-skylib-1.3.0.tar.gz",
+    ],
+    sha256 = "74d544d96f4a5bb630d465ca8bbcfe231e3594e5aae57e1edbf17a6eb3ca2506",
+)
+
+load("@bazel_skylib//:workspace.bzl", "bazel_skylib_workspace")
+bazel_skylib_workspace()

externals/catch/appveyor.yml

@@ -0,0 +1,129 @@
+version: "{build}-{branch}"
+
+# If we ever get a backlog larger than clone_depth, builds will fail
+# spuriously. I do not think we will ever get 20 deep commits deep though.
+clone_depth: 20
+
+# We want to build everything, except for branches that are explicitly
+# for messing around with travis.
+branches:
+  except:
+    - /dev-travis.+/
+
+
+# We need a more up to date pip because Python 2.7 is EOL soon
+init:
+  - set PATH=C:\Python35;C:\Python35\Scripts;%PATH%
+
+
+install:
+  - ps: if (($env:CONFIGURATION) -eq "Debug" -And ($env:coverage) -eq "1" ) { pip --disable-pip-version-check install codecov }
+  # This removes our changes to PATH. Keep this step last!
+  - ps: if (($env:CONFIGURATION) -eq "Debug" -And ($env:coverage) -eq "1" ) { .\tools\misc\installOpenCppCoverage.ps1 }
+
+
+before_build:
+  # We need to modify PATH again, because it was reset since the "init" step
+  - set PATH=C:\Python35;C:\Python35\Scripts;%PATH%
+  - set CXXFLAGS=%additional_flags%
+  # If we are building examples/extra-tests, we need to regenerate the amalgamated files
+  - cmd: if "%examples%"=="1" ( python .\tools\scripts\generateAmalgamatedFiles.py )
+  # Indirection because appveyor doesn't handle multiline batch scripts properly
+  # https://stackoverflow.com/questions/37627248/how-to-split-a-command-over-multiple-lines-in-appveyor-yml/37647169#37647169
+  # https://help.appveyor.com/discussions/questions/3888-multi-line-cmd-or-powershell-warning-ignore
+  - cmd: .\tools\misc\appveyorBuildConfigurationScript.bat
+
+
+# build with MSBuild
+build:
+  project: Build\Catch2.sln             # path to Visual Studio solution or project
+  parallel: true                        # enable MSBuild parallel builds
+  verbosity: normal                     # MSBuild verbosity level {quiet|minimal|normal|detailed}
+
+test_script:
+  - set CTEST_OUTPUT_ON_FAILURE=1
+  - cmd: .\tools\misc\appveyorTestRunScript.bat
+
+
+# Sadly we cannot use the standard "dimensions" based approach towards
+# specifying the different builds, as there is no way to add one-offs
+# builds afterwards. This means that we will painfully specify each
+# build explicitly.
+environment:
+  matrix:
+    - FLAVOR: VS 2019 x64 Debug Surrogates Configure Tests
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      surrogates: 1
+      configure_tests: 1
+      platform: x64
+      configuration: Debug
+    
+    - FLAVOR: VS 2019 x64 Release
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      platform: x64
+      configuration: Release
+
+    - FLAVOR: VS 2019 x64 Debug Coverage Examples
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      examples: 1
+      coverage: 1
+      platform: x64
+      configuration: Debug
+
+    - FLAVOR: VS 2019 x64 Debug WMain
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      wmain: 1
+      additional_flags: "/D_UNICODE /DUNICODE"
+      platform: x64
+      configuration: Debug
+
+    - FLAVOR: VS 2019 Win32 Debug
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      platform: Win32
+      configuration: Debug
+
+    - FLAVOR: VS 2019 x64 Debug Latest Strict
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
+      additional_flags: "/permissive- /std:c++latest"
+      platform: x64
+      configuration: Debug
+
+    - FLAVOR: VS 2017 x64 Debug
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      platform: x64
+      configuration: Debug
+    
+    - FLAVOR: VS 2017 x64 Release
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      platform: x64
+      configuration: Release
+
+    - FLAVOR: VS 2017 x64 Release Coverage
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      coverage: 1
+      platform: x64
+      configuration: Debug
+
+    - FLAVOR: VS 2017 Win32 Debug
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      platform: Win32
+      configuration: Debug
+
+    - FLAVOR: VS 2017 Win32 Debug Examples
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      examples: 1
+      platform: Win32
+      configuration: Debug
+
+    - FLAVOR: VS 2017 Win32 Debug WMain
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      wmain: 1
+      additional_flags: "/D_UNICODE /DUNICODE"
+      platform: Win32
+      configuration: Debug
+
+    - FLAVOR: VS 2017 x64 Debug Latest Strict
+      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
+      additional_flags: "/permissive- /std:c++latest"
+      platform: x64
+      configuration: Debug

externals/catch/codecov.yml

@@ -0,0 +1,22 @@
+coverage:
+  precision: 2
+  round: nearest
+  range: "60...90"
+  status:
+    project:
+      default:
+        threshold: 2%
+    patch:
+      default:
+        target: 80%
+  ignore:
+    - "**/external/clara.hpp"
+    - "tests"
+
+
+codecov:
+  branch: devel
+  max_report_age: off
+
+comment:
+  layout: "diff"

externals/catch/conanfile.py

@@ -0,0 +1,60 @@
+#!/usr/bin/env python
+from conans import ConanFile, CMake, tools
+
+class CatchConan(ConanFile):
+    name = "catch2"
+    description = "A modern, C++-native, framework for unit-tests, TDD and BDD"
+    topics = ("conan", "catch2", "unit-test", "tdd", "bdd")
+    url = "https://github.com/catchorg/Catch2"
+    homepage = url
+    license = "BSL-1.0"
+
+    exports = "LICENSE.txt"
+    exports_sources = ("src/*", "CMakeLists.txt", "CMake/*", "extras/*")
+
+    settings = "os", "compiler", "build_type", "arch"
+
+    generators = "cmake"
+
+    def _configure_cmake(self):
+        cmake = CMake(self)
+        cmake.definitions["BUILD_TESTING"] = "OFF"
+        cmake.definitions["CATCH_INSTALL_DOCS"] = "OFF"
+        cmake.definitions["CATCH_INSTALL_EXTRAS"] = "ON"
+        cmake.configure(build_folder="build")
+        return cmake
+
+    def build(self):
+        # We need this workaround until the toolchains feature
+        # to inject stuff like MD/MT
+        line_to_replace = 'list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/CMake")'
+        tools.replace_in_file("CMakeLists.txt", line_to_replace,
+                              '''{}
+include("{}/conanbuildinfo.cmake")
+conan_basic_setup()'''.format(line_to_replace, self.install_folder.replace("\\", "/")))
+
+        cmake = self._configure_cmake()
+        cmake.build()
+
+    def package(self):
+        self.copy(pattern="LICENSE.txt", dst="licenses")
+        cmake = self._configure_cmake()
+        cmake.install()
+
+    def package_info(self):
+        lib_suffix = "d" if self.settings.build_type == "Debug" else ""
+
+        self.cpp_info.names["cmake_find_package"] = "Catch2"
+        self.cpp_info.names["cmake_find_package_multi"] = "Catch2"
+        # Catch2
+        self.cpp_info.components["catch2base"].names["cmake_find_package"] = "Catch2"
+        self.cpp_info.components["catch2base"].names["cmake_find_package_multi"] = "Catch2"
+        self.cpp_info.components["catch2base"].names["pkg_config"] = "Catch2"
+        self.cpp_info.components["catch2base"].libs = ["Catch2" + lib_suffix]
+        self.cpp_info.components["catch2base"].builddirs.append("lib/cmake/Catch2")
+        # Catch2WithMain
+        self.cpp_info.components["catch2main"].names["cmake_find_package"] = "Catch2WithMain"
+        self.cpp_info.components["catch2main"].names["cmake_find_package_multi"] = "Catch2WithMain"
+        self.cpp_info.components["catch2main"].names["pkg_config"] = "Catch2WithMain"
+        self.cpp_info.components["catch2main"].libs = ["Catch2Main" + lib_suffix]
+        self.cpp_info.components["catch2main"].requires = ["catch2base"]

externals/catch/docs/Readme.md

@@ -0,0 +1,42 @@
+<a id="top"></a>
+# Reference
+
+To get the most out of Catch2, start with the [tutorial](tutorial.md#top).
+Once you're up and running consider the following reference material.
+
+**Writing tests:**
+* [Assertion macros](assertions.md#top)
+* [Matchers (asserting complex properties)](matchers.md#top)
+* [Comparing floating point numbers](comparing-floating-point-numbers.md#top)
+* [Logging macros](logging.md#top)
+* [Test cases and sections](test-cases-and-sections.md#top)
+* [Test fixtures](test-fixtures.md#top)
+* [Reporters (output customization)](reporters.md#top)
+* [Event Listeners](event-listeners.md#top)
+* [Data Generators (value parameterized tests)](generators.md#top)
+* [Other macros](other-macros.md#top)
+* [Micro benchmarking](benchmarks.md#top)
+
+**Fine tuning:**
+* [Supplying your own main()](own-main.md#top)
+* [Compile-time configuration](configuration.md#top)
+* [String Conversions](tostring.md#top)
+
+**Running:**
+* [Command line](command-line.md#top)
+
+**Odds and ends:**
+* [Frequently Asked Questions (FAQ)](faq.md#top)
+* [Best practices and other tips](usage-tips.md#top)
+* [CMake integration](cmake-integration.md#top)
+* [Tooling integration (CI, test runners, other)](ci-and-misc.md#top)
+* [Known limitations](limitations.md#top)
+
+**Other:**
+* [Why Catch2?](why-catch.md#top)
+* [Migrating from v2 to v3](migrate-v2-to-v3.md#top)
+* [Open Source Projects using Catch2](opensource-users.md#top)
+* [Commercial Projects using Catch2](commercial-users.md#top)
+* [Contributing](contributing.md#top)
+* [Release Notes](release-notes.md#top)
+* [Deprecations and incoming changes](deprecations.md#top)

externals/catch/docs/assertions.md

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+<a id="top"></a>
+# Assertion Macros
+
+**Contents**<br>
+[Natural Expressions](#natural-expressions)<br>
+[Floating point comparisons](#floating-point-comparisons)<br>
+[Exceptions](#exceptions)<br>
+[Matcher expressions](#matcher-expressions)<br>
+[Thread Safety](#thread-safety)<br>
+[Expressions with commas](#expressions-with-commas)<br>
+
+Most test frameworks have a large collection of assertion macros to capture all possible conditional forms (```_EQUALS```, ```_NOTEQUALS```, ```_GREATER_THAN``` etc).
+
+Catch is different. Because it decomposes natural C-style conditional expressions most of these forms are reduced to one or two that you will use all the time. That said there is a rich set of auxiliary macros as well. We'll describe all of these here.
+
+Most of these macros come in two forms:
+
+## Natural Expressions
+
+The ```REQUIRE``` family of macros tests an expression and aborts the test case if it fails.
+The ```CHECK``` family are equivalent but execution continues in the same test case even if the assertion fails. This is useful if you have a series of essentially orthogonal assertions and it is useful to see all the results rather than stopping at the first failure.
+
+* **REQUIRE(** _expression_ **)** and
+* **CHECK(** _expression_ **)**
+
+Evaluates the expression and records the result. If an exception is thrown, it is caught, reported, and counted as a failure. These are the macros you will use most of the time.
+
+Examples:
+```
+CHECK( str == "string value" );
+CHECK( thisReturnsTrue() );
+REQUIRE( i == 42 );
+```
+
+Expressions prefixed with `!` cannot be decomposed. If you have a type
+that is convertible to bool and you want to assert that it evaluates to
+false, use the two forms below:
+
+
+* **REQUIRE_FALSE(** _expression_ **)** and
+* **CHECK_FALSE(** _expression_ **)**
+
+Note that there is no reason to use these forms for plain bool variables,
+because there is no added value in decomposing them.
+
+Example:
+```cpp
+Status ret = someFunction();
+REQUIRE_FALSE(ret); // ret must evaluate to false, and Catch2 will print
+                    // out the value of ret if possibly
+```
+
+
+### Other limitations
+
+Note that expressions containing either of the binary logical operators,
+`&&` or `||`, cannot be decomposed and will not compile. The reason behind
+this is that it is impossible to overload `&&` and `||` in a way that
+keeps their short-circuiting semantics, and expression decomposition
+relies on overloaded operators to work.
+
+Simple example of an issue with overloading binary logical operators
+is a common pointer idiom, `p && p->foo == 2`. Using the built-in `&&`
+operator, `p` is only dereferenced if it is not null. With overloaded
+`&&`, `p` is always dereferenced, thus causing a segfault if
+`p == nullptr`.
+
+If you want to test expression that contains `&&` or `||`, you have two
+options.
+
+1) Enclose it in parentheses. Parentheses force evaluation of the expression
+   before the expression decomposition can touch it, and thus it cannot
+   be used.
+
+2) Rewrite the expression. `REQUIRE(a == 1 && b == 2)` can always be split
+   into `REQUIRE(a == 1); REQUIRE(b == 2);`. Alternatively, if this is a
+   common pattern in your tests, think about using [Matchers](#matcher-expressions).
+   instead. There is no simple rewrite rule for `||`, but I generally
+   believe that if you have `||` in your test expression, you should rethink
+   your tests.
+
+
+## Floating point comparisons
+
+Comparing floating point numbers is complex, and [so it has its own
+documentation page](comparing-floating-point-numbers.md#top).
+
+
+## Exceptions
+
+* **REQUIRE_NOTHROW(** _expression_ **)** and
+* **CHECK_NOTHROW(** _expression_ **)**
+
+Expects that no exception is thrown during evaluation of the expression.
+
+* **REQUIRE_THROWS(** _expression_ **)** and
+* **CHECK_THROWS(** _expression_ **)**
+
+Expects that an exception (of any type) is be thrown during evaluation of the expression.
+
+* **REQUIRE_THROWS_AS(** _expression_, _exception type_ **)** and
+* **CHECK_THROWS_AS(** _expression_, _exception type_ **)**
+
+Expects that an exception of the _specified type_ is thrown during evaluation of the expression. Note that the _exception type_ is extended with `const&` and you should not include it yourself.
+
+* **REQUIRE_THROWS_WITH(** _expression_, _string or string matcher_ **)** and
+* **CHECK_THROWS_WITH(** _expression_, _string or string matcher_ **)**
+
+Expects that an exception is thrown that, when converted to a string, matches the _string_ or _string matcher_ provided (see next section for Matchers).
+
+e.g.
+```cpp
+REQUIRE_THROWS_WITH( openThePodBayDoors(), Contains( "afraid" ) && Contains( "can't do that" ) );
+REQUIRE_THROWS_WITH( dismantleHal(), "My mind is going" );
+```
+
+* **REQUIRE_THROWS_MATCHES(** _expression_, _exception type_, _matcher for given exception type_ **)** and
+* **CHECK_THROWS_MATCHES(** _expression_, _exception type_, _matcher for given exception type_ **)**
+
+Expects that exception of _exception type_ is thrown and it matches provided matcher (see the [documentation for Matchers](matchers.md#top)).
+
+
+_Please note that the `THROW` family of assertions expects to be passed a single expression, not a statement or series of statements. If you want to check a more complicated sequence of operations, you can use a C++11 lambda function._
+
+```cpp
+REQUIRE_NOTHROW([&](){
+    int i = 1;
+    int j = 2;
+    auto k = i + j;
+    if (k == 3) {
+        throw 1;
+    }
+}());
+```
+
+
+
+## Matcher expressions
+
+To support Matchers a slightly different form is used. Matchers have [their own documentation](matchers.md#top).
+
+* **REQUIRE_THAT(** _lhs_, _matcher expression_ **)** and
+* **CHECK_THAT(** _lhs_, _matcher expression_ **)**
+
+Matchers can be composed using `&&`, `||` and `!` operators.
+
+## Thread Safety
+
+Currently assertions in Catch are not thread safe.
+For more details, along with workarounds, see the section on [the limitations page](limitations.md#thread-safe-assertions).
+
+## Expressions with commas
+
+Because the preprocessor parses code using different rules than the
+compiler, multiple-argument assertions (e.g. `REQUIRE_THROWS_AS`) have
+problems with commas inside the provided expressions. As an example
+`REQUIRE_THROWS_AS(std::pair<int, int>(1, 2), std::invalid_argument);`
+will fail to compile, because the preprocessor sees 3 arguments provided,
+but the macro accepts only 2. There are two possible workarounds.
+
+1) Use typedef:
+```cpp
+using int_pair = std::pair<int, int>;
+REQUIRE_THROWS_AS(int_pair(1, 2), std::invalid_argument);
+```
+
+This solution is always applicable, but makes the meaning of the code
+less clear.
+
+2) Parenthesize the expression:
+```cpp
+TEST_CASE_METHOD((Fixture<int, int>), "foo", "[bar]") {
+    SUCCEED();
+}
+```
+
+This solution is not always applicable, because it might require extra
+changes on the Catch's side to work.
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/benchmarks.md

@@ -0,0 +1,251 @@
+<a id="top"></a>
+# Authoring benchmarks
+
+> [Introduced](https://github.com/catchorg/Catch2/issues/1616) in Catch2 2.9.0.
+
+Writing benchmarks is not easy. Catch simplifies certain aspects but you'll
+always need to take care about various aspects. Understanding a few things about
+the way Catch runs your code will be very helpful when writing your benchmarks.
+
+First off, let's go over some terminology that will be used throughout this
+guide.
+
+- *User code*: user code is the code that the user provides to be measured.
+- *Run*: one run is one execution of the user code. Sometimes also referred
+  to as an _iteration_.
+- *Sample*: one sample is one data point obtained by measuring the time it takes
+  to perform a certain number of runs. One sample can consist of more than one
+  run if the clock available does not have enough resolution to accurately
+  measure a single run. All samples for a given benchmark execution are obtained
+  with the same number of runs.
+
+## Execution procedure
+
+Now I can explain how a benchmark is executed in Catch. There are three main
+steps, though the first does not need to be repeated for every benchmark.
+
+1. *Environmental probe*: before any benchmarks can be executed, the clock's
+resolution is estimated. A few other environmental artifacts are also estimated
+at this point, like the cost of calling the clock function, but they almost
+never have any impact in the results.
+
+2. *Estimation*: the user code is executed a few times to obtain an estimate of
+the amount of runs that should be in each sample. This also has the potential
+effect of bringing relevant code and data into the caches before the actual
+measurement starts.
+
+3. *Measurement*: all the samples are collected sequentially by performing the
+number of runs estimated in the previous step for each sample.
+
+This already gives us one important rule for writing benchmarks for Catch: the
+benchmarks must be repeatable. The user code will be executed several times, and
+the number of times it will be executed during the estimation step cannot be
+known beforehand since it depends on the time it takes to execute the code.
+User code that cannot be executed repeatedly will lead to bogus results or
+crashes.
+
+## Benchmark specification
+
+Benchmarks can be specified anywhere inside a Catch test case.
+There is a simple and a slightly more advanced version of the `BENCHMARK` macro.
+
+Let's have a look how a naive Fibonacci implementation could be benchmarked:
+```c++
+std::uint64_t Fibonacci(std::uint64_t number) {
+    return number < 2 ? 1 : Fibonacci(number - 1) + Fibonacci(number - 2);
+}
+```
+Now the most straight forward way to benchmark this function, is just adding a `BENCHMARK` macro to our test case:
+```c++
+TEST_CASE("Fibonacci") {
+    CHECK(Fibonacci(0) == 1);
+    // some more asserts..
+    CHECK(Fibonacci(5) == 8);
+    // some more asserts..
+
+    // now let's benchmark:
+    BENCHMARK("Fibonacci 20") {
+        return Fibonacci(20);
+    };
+
+    BENCHMARK("Fibonacci 25") {
+        return Fibonacci(25);
+    };
+
+    BENCHMARK("Fibonacci 30") {
+        return Fibonacci(30);
+    };
+
+    BENCHMARK("Fibonacci 35") {
+        return Fibonacci(35);
+    };
+}
+```
+There's a few things to note:
+- As `BENCHMARK` expands to a lambda expression it is necessary to add a semicolon after
+ the closing brace (as opposed to the first experimental version).
+- The `return` is a handy way to avoid the compiler optimizing away the benchmark code.
+
+Running this already runs the benchmarks and outputs something similar to:
+```
+-------------------------------------------------------------------------------
+Fibonacci
+-------------------------------------------------------------------------------
+C:\path\to\Catch2\Benchmark.tests.cpp(10)
+...............................................................................
+benchmark name                                  samples       iterations    estimated
+                                                mean          low mean      high mean
+                                                std dev       low std dev   high std dev
+-------------------------------------------------------------------------------
+Fibonacci 20                                            100       416439   83.2878 ms
+                                                       2 ns         2 ns         2 ns
+                                                       0 ns         0 ns         0 ns
+
+Fibonacci 25                                            100       400776   80.1552 ms
+                                                       3 ns         3 ns         3 ns
+                                                       0 ns         0 ns         0 ns
+
+Fibonacci 30                                            100       396873   79.3746 ms
+                                                      17 ns        17 ns        17 ns
+                                                       0 ns         0 ns         0 ns
+
+Fibonacci 35                                            100       145169   87.1014 ms
+                                                     468 ns       464 ns       473 ns
+                                                      21 ns        15 ns        34 ns
+```
+
+### Advanced benchmarking
+The simplest use case shown above, takes no arguments and just runs the user code that needs to be measured.
+However, if using the `BENCHMARK_ADVANCED` macro and adding a `Catch::Benchmark::Chronometer` argument after
+the macro, some advanced features are available. The contents of the simple benchmarks are invoked once per run,
+while the blocks of the advanced benchmarks are invoked exactly twice:
+once during the estimation phase, and another time during the execution phase.
+
+```c++
+BENCHMARK("simple"){ return long_computation(); };
+
+BENCHMARK_ADVANCED("advanced")(Catch::Benchmark::Chronometer meter) {
+    set_up();
+    meter.measure([] { return long_computation(); });
+};
+```
+
+These advanced benchmarks no longer consist entirely of user code to be measured.
+In these cases, the code to be measured is provided via the
+`Catch::Benchmark::Chronometer::measure` member function. This allows you to set up any
+kind of state that might be required for the benchmark but is not to be included
+in the measurements, like making a vector of random integers to feed to a
+sorting algorithm.
+
+A single call to `Catch::Benchmark::Chronometer::measure` performs the actual measurements
+by invoking the callable object passed in as many times as necessary. Anything
+that needs to be done outside the measurement can be done outside the call to
+`measure`.
+
+The callable object passed in to `measure` can optionally accept an `int`
+parameter.
+
+```c++
+meter.measure([](int i) { return long_computation(i); });
+```
+
+If it accepts an `int` parameter, the sequence number of each run will be passed
+in, starting with 0. This is useful if you want to measure some mutating code,
+for example. The number of runs can be known beforehand by calling
+`Catch::Benchmark::Chronometer::runs`; with this one can set up a different instance to be
+mutated by each run.
+
+```c++
+std::vector<std::string> v(meter.runs());
+std::fill(v.begin(), v.end(), test_string());
+meter.measure([&v](int i) { in_place_escape(v[i]); });
+```
+
+Note that it is not possible to simply use the same instance for different runs
+and resetting it between each run since that would pollute the measurements with
+the resetting code.
+
+It is also possible to just provide an argument name to the simple `BENCHMARK` macro to get
+the same semantics as providing a callable to `meter.measure` with `int` argument:
+
+```c++
+BENCHMARK("indexed", i){ return long_computation(i); };
+```
+
+### Constructors and destructors
+
+All of these tools give you a lot mileage, but there are two things that still
+need special handling: constructors and destructors. The problem is that if you
+use automatic objects they get destroyed by the end of the scope, so you end up
+measuring the time for construction and destruction together. And if you use
+dynamic allocation instead, you end up including the time to allocate memory in
+the measurements.
+
+To solve this conundrum, Catch provides class templates that let you manually
+construct and destroy objects without dynamic allocation and in a way that lets
+you measure construction and destruction separately.
+
+```c++
+BENCHMARK_ADVANCED("construct")(Catch::Benchmark::Chronometer meter) {
+    std::vector<Catch::Benchmark::storage_for<std::string>> storage(meter.runs());
+    meter.measure([&](int i) { storage[i].construct("thing"); });
+};
+
+BENCHMARK_ADVANCED("destroy")(Catch::Benchmark::Chronometer meter) {
+    std::vector<Catch::Benchmark::destructable_object<std::string>> storage(meter.runs());
+    for(auto&& o : storage)
+        o.construct("thing");
+    meter.measure([&](int i) { storage[i].destruct(); });
+};
+```
+
+`Catch::Benchmark::storage_for<T>` objects are just pieces of raw storage suitable for `T`
+objects. You can use the `Catch::Benchmark::storage_for::construct` member function to call a constructor and
+create an object in that storage. So if you want to measure the time it takes
+for a certain constructor to run, you can just measure the time it takes to run
+this function.
+
+When the lifetime of a `Catch::Benchmark::storage_for<T>` object ends, if an actual object was
+constructed there it will be automatically destroyed, so nothing leaks.
+
+If you want to measure a destructor, though, we need to use
+`Catch::Benchmark::destructable_object<T>`. These objects are similar to
+`Catch::Benchmark::storage_for<T>` in that construction of the `T` object is manual, but
+it does not destroy anything automatically. Instead, you are required to call
+the `Catch::Benchmark::destructable_object::destruct` member function, which is what you
+can use to measure the destruction time.
+
+### The optimizer
+
+Sometimes the optimizer will optimize away the very code that you want to
+measure. There are several ways to use results that will prevent the optimiser
+from removing them. You can use the `volatile` keyword, or you can output the
+value to standard output or to a file, both of which force the program to
+actually generate the value somehow.
+
+Catch adds a third option. The values returned by any function provided as user
+code are guaranteed to be evaluated and not optimised out. This means that if
+your user code consists of computing a certain value, you don't need to bother
+with using `volatile` or forcing output. Just `return` it from the function.
+That helps with keeping the code in a natural fashion.
+
+Here's an example:
+
+```c++
+// may measure nothing at all by skipping the long calculation since its
+// result is not used
+BENCHMARK("no return"){ long_calculation(); };
+
+// the result of long_calculation() is guaranteed to be computed somehow
+BENCHMARK("with return"){ return long_calculation(); };
+```
+
+However, there's no other form of control over the optimizer whatsoever. It is
+up to you to write a benchmark that actually measures what you want and doesn't
+just measure the time to do a whole bunch of nothing.
+
+To sum up, there are two simple rules: whatever you would do in handwritten code
+to control optimization still works in Catch; and Catch makes return values
+from user code into observable effects that can't be optimized away.
+
+<i>Adapted from nonius' documentation.</i>

externals/catch/docs/ci-and-misc.md

@@ -0,0 +1,110 @@
+<a id="top"></a>
+# Tooling integration (CI, test runners and so on)
+
+**Contents**<br>
+[Continuous Integration systems](#continuous-integration-systems)<br>
+[Bazel test runner integration](#bazel-test-runner-integration)<br>
+[Low-level tools](#low-level-tools)<br>
+[CMake](#cmake)<br>
+
+This page talks about Catch2's integration with other related tooling,
+like Continuous Integration and 3rd party test runners.
+
+
+## Continuous Integration systems
+
+Probably the most important aspect to using Catch with a build server is the use of different reporters. Catch comes bundled with three reporters that should cover the majority of build servers out there - although adding more for better integration with some is always a possibility (currently we also offer TeamCity, TAP, Automake and SonarQube reporters).
+
+Two of these reporters are built in (XML and JUnit) and the third (TeamCity) is included as a separate header. It's possible that the other two may be split out in the future too - as that would make the core of Catch smaller for those that don't need them.
+
+### XML Reporter
+```-r xml```
+
+The XML Reporter writes in an XML format that is specific to Catch.
+
+The advantage of this format is that it corresponds well to the way Catch works (especially the more unusual features, such as nested sections) and is a fully streaming format - that is it writes output as it goes, without having to store up all its results before it can start writing.
+
+The disadvantage is that, being specific to Catch, no existing build servers understand the format natively. It can be used as input to an XSLT transformation that could convert it to, say, HTML - although this loses the streaming advantage, of course.
+
+### JUnit Reporter
+```-r junit```
+
+The JUnit Reporter writes in an XML format that mimics the JUnit ANT schema.
+
+The advantage of this format is that the JUnit Ant schema is widely understood by most build servers and so can usually be consumed with no additional work.
+
+The disadvantage is that this schema was designed to correspond to how JUnit works - and there is a significant mismatch with how Catch works. Additionally the format is not streamable (because opening elements hold counts of failed and passing tests as attributes) - so the whole test run must complete before it can be written.
+
+
+### TeamCity Reporter
+```-r teamcity```
+
+The TeamCity Reporter writes TeamCity service messages to stdout. In order to be able to use this reporter an additional header must also be included.
+
+Being specific to TeamCity this is the best reporter to use with it - but it is completely unsuitable for any other purpose. It is a streaming format (it writes as it goes) - although test results don't appear in the TeamCity interface until the completion of a suite (usually the whole test run).
+
+### Automake Reporter
+```-r automake```
+
+The Automake Reporter writes out the [meta tags](https://www.gnu.org/software/automake/manual/html_node/Log-files-generation-and-test-results-recording.html#Log-files-generation-and-test-results-recording) expected by automake via `make check`.
+
+### TAP (Test Anything Protocol) Reporter
+```-r tap```
+
+Because of the incremental nature of Catch's test suites and ability to run specific tests, our implementation of TAP reporter writes out the number of tests in a suite last.
+
+### SonarQube Reporter
+```-r sonarqube```
+[SonarQube Generic Test Data](https://docs.sonarqube.org/latest/analysis/generic-test/) XML format for tests metrics.
+
+
+## Bazel test runner integration
+
+Catch2 understands some of the environment variables Bazel uses to control
+test execution. Specifically it understands
+
+ * JUnit output path via `XML_OUTPUT_FILE`
+ * Test filtering via `TESTBRIDGE_TEST_ONLY`
+ * Test sharding via `TEST_SHARD_INDEX`, `TEST_TOTAL_SHARDS`, and `TEST_SHARD_STATUS_FILE`
+
+> Support for `XML_OUTPUT_FILE` was [introduced](https://github.com/catchorg/Catch2/pull/2399) in Catch2 3.0.1
+
+> Support for `TESTBRIDGE_TEST_ONLY` and sharding was introduced in Catch2 3.2.0
+
+This integration is enabled via either a [compile time configuration
+option](configuration.md#bazel-support), or via `BAZEL_TEST` environment
+variable set to "1".
+
+> Support for `BAZEL_TEST` was [introduced](https://github.com/catchorg/Catch2/pull/2459) in Catch2 3.1.0
+
+
+## Low-level tools
+
+### CodeCoverage module (GCOV, LCOV...)
+
+If you are using GCOV tool to get testing coverage of your code, and are not sure how to integrate it with CMake and Catch, there should be an external example over at https://github.com/fkromer/catch_cmake_coverage
+
+
+### pkg-config
+
+Catch2 provides a rudimentary pkg-config integration, by registering itself
+under the name `catch2`. This means that after Catch2 is installed, you
+can use `pkg-config` to get its include path: `pkg-config --cflags catch2`.
+
+### gdb and lldb scripts
+
+Catch2's `extras` folder also contains two simple debugger scripts,
+`gdbinit` for `gdb` and `lldbinit` for `lldb`. If loaded into their
+respective debugger, these will tell it to step over Catch2's internals
+when stepping through code.
+
+
+## CMake
+
+[As it has been getting kinda long, the documentation of Catch2's
+integration with CMake has been moved to its own page.](cmake-integration.md#top)
+
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/cmake-integration.md

@@ -0,0 +1,402 @@
+<a id="top"></a>
+# CMake integration
+
+**Contents**<br>
+[CMake targets](#cmake-targets)<br>
+[Automatic test registration](#automatic-test-registration)<br>
+[CMake project options](#cmake-project-options)<br>
+[`CATCH_CONFIG_*` customization options in CMake](#catch_config_-customization-options-in-cmake)<br>
+[Installing Catch2 from git repository](#installing-catch2-from-git-repository)<br>
+[Installing Catch2 from vcpkg](#installing-catch2-from-vcpkg)<br>
+
+Because we use CMake to build Catch2, we also provide a couple of
+integration points for our users.
+
+1) Catch2 exports a (namespaced) CMake target
+2) Catch2's repository contains CMake scripts for automatic registration
+of `TEST_CASE`s in CTest
+
+## CMake targets
+
+Catch2's CMake build exports two targets, `Catch2::Catch2`, and
+`Catch2::Catch2WithMain`. If you do not need custom `main` function,
+you should be using the latter (and only the latter). Linking against
+it will add the proper include paths and link your target together with
+2 static libraries that implement Catch2 and its main respectively.
+If you need custom `main`, you should link only against `Catch2::Catch2`.
+
+This means that if Catch2 has been installed on the system, it should
+be enough to do
+```cmake
+find_package(Catch2 3 REQUIRED)
+# These tests can use the Catch2-provided main
+add_executable(tests test.cpp)
+target_link_libraries(tests PRIVATE Catch2::Catch2WithMain)
+
+# These tests need their own main
+add_executable(custom-main-tests test.cpp test-main.cpp)
+target_link_libraries(custom-main-tests PRIVATE Catch2::Catch2)
+```
+
+These targets are also provided when Catch2 is used as a subdirectory.
+Assuming Catch2 has been cloned to `lib/Catch2`, you only need to replace
+the `find_package` call with `add_subdirectory(lib/Catch2)` and the snippet
+above still works.
+
+
+Another possibility is to use [FetchContent](https://cmake.org/cmake/help/latest/module/FetchContent.html):
+```cmake
+Include(FetchContent)
+
+FetchContent_Declare(
+  Catch2
+  GIT_REPOSITORY https://github.com/catchorg/Catch2.git
+  GIT_TAG        v3.0.1 # or a later release
+)
+
+FetchContent_MakeAvailable(Catch2)
+
+add_executable(tests test.cpp)
+target_link_libraries(tests PRIVATE Catch2::Catch2WithMain)
+```
+
+
+## Automatic test registration
+
+Catch2's repository also contains three CMake scripts that help users
+with automatically registering their `TEST_CASE`s with CTest. They
+can be found in the `extras` folder, and are
+
+1) `Catch.cmake` (and its dependency `CatchAddTests.cmake`)
+2) `ParseAndAddCatchTests.cmake` (deprecated)
+3) `CatchShardTests.cmake` (and its dependency `CatchShardTestsImpl.cmake`)
+
+If Catch2 has been installed in system, both of these can be used after
+doing `find_package(Catch2 REQUIRED)`. Otherwise you need to add them
+to your CMake module path.
+
+<a id="catch_discover_tests"></a>
+### `Catch.cmake` and `CatchAddTests.cmake`
+
+`Catch.cmake` provides function `catch_discover_tests` to get tests from
+a target. This function works by running the resulting executable with
+`--list-test-names-only` flag, and then parsing the output to find all
+existing tests.
+
+#### Usage
+```cmake
+cmake_minimum_required(VERSION 3.5)
+
+project(baz LANGUAGES CXX VERSION 0.0.1)
+
+find_package(Catch2 REQUIRED)
+add_executable(foo test.cpp)
+target_link_libraries(foo PRIVATE Catch2::Catch2)
+
+include(CTest)
+include(Catch)
+catch_discover_tests(foo)
+```
+
+When using `FetchContent`, `include(Catch)` will fail unless
+`CMAKE_MODULE_PATH` is explicitly updated to include the extras
+directory.
+
+```cmake
+# ... FetchContent ...
+#
+list(APPEND CMAKE_MODULE_PATH ${catch2_SOURCE_DIR}/extras)
+include(CTest)
+include(Catch)
+catch_discover_tests()
+```
+
+#### Customization
+`catch_discover_tests` can be given several extra arguments:
+```cmake
+catch_discover_tests(target
+                     [TEST_SPEC arg1...]
+                     [EXTRA_ARGS arg1...]
+                     [WORKING_DIRECTORY dir]
+                     [TEST_PREFIX prefix]
+                     [TEST_SUFFIX suffix]
+                     [PROPERTIES name1 value1...]
+                     [TEST_LIST var]
+                     [REPORTER reporter]
+                     [OUTPUT_DIR dir]
+                     [OUTPUT_PREFIX prefix]
+                     [OUTPUT_SUFFIX suffix]
+)
+```
+
+* `TEST_SPEC arg1...`
+
+Specifies test cases, wildcarded test cases, tags and tag expressions to
+pass to the Catch executable alongside the `--list-test-names-only` flag.
+
+
+* `EXTRA_ARGS arg1...`
+
+Any extra arguments to pass on the command line to each test case.
+
+
+* `WORKING_DIRECTORY dir`
+
+Specifies the directory in which to run the discovered test cases.  If this
+option is not provided, the current binary directory is used.
+
+
+* `TEST_PREFIX prefix`
+
+Specifies a _prefix_ to be added to the name of each discovered test case.
+This can be useful when the same test executable is being used in multiple
+calls to `catch_discover_tests()`, with different `TEST_SPEC` or `EXTRA_ARGS`.
+
+
+* `TEST_SUFFIX suffix`
+
+Same as `TEST_PREFIX`, except it specific the _suffix_ for the test names.
+Both `TEST_PREFIX` and `TEST_SUFFIX` can be specified at the same time.
+
+
+* `PROPERTIES name1 value1...`
+
+Specifies additional properties to be set on all tests discovered by this
+invocation of `catch_discover_tests`.
+
+
+* `TEST_LIST var`
+
+Make the list of tests available in the variable `var`, rather than the
+default `<target>_TESTS`.  This can be useful when the same test
+executable is being used in multiple calls to `catch_discover_tests()`.
+Note that this variable is only available in CTest.
+
+* `REPORTER reporter`
+
+Use the specified reporter when running the test case. The reporter will
+be passed to the test runner as `--reporter reporter`.
+
+* `OUTPUT_DIR dir`
+
+If specified, the parameter is passed along as
+`--out dir/<test_name>` to test executable. The actual file name is the
+same as the test name. This should be used instead of
+`EXTRA_ARGS --out foo` to avoid race conditions writing the result output
+when using parallel test execution.
+
+* `OUTPUT_PREFIX prefix`
+
+May be used in conjunction with `OUTPUT_DIR`.
+If specified, `prefix` is added to each output file name, like so
+`--out dir/prefix<test_name>`.
+
+* `OUTPUT_SUFFIX suffix`
+
+May be used in conjunction with `OUTPUT_DIR`.
+If specified, `suffix` is added to each output file name, like so
+`--out dir/<test_name>suffix`. This can be used to add a file extension to
+the output file name e.g. ".xml".
+
+
+### `ParseAndAddCatchTests.cmake`
+
+⚠ This script is [deprecated](https://github.com/catchorg/Catch2/pull/2120)
+in Catch2 2.13.4 and superseded by the above approach using `catch_discover_tests`.
+See [#2092](https://github.com/catchorg/Catch2/issues/2092) for details.
+
+`ParseAndAddCatchTests` works by parsing all implementation files
+associated with the provided target, and registering them via CTest's
+`add_test`. This approach has some limitations, such as the fact that
+commented-out tests will be registered anyway. More serious, only a
+subset of the assertion macros currently available in Catch can be
+detected by this script and tests with any macros that cannot be
+parsed are *silently ignored*.
+
+
+#### Usage
+
+```cmake
+cmake_minimum_required(VERSION 3.5)
+
+project(baz LANGUAGES CXX VERSION 0.0.1)
+
+find_package(Catch2 REQUIRED)
+add_executable(foo test.cpp)
+target_link_libraries(foo PRIVATE Catch2::Catch2)
+
+include(CTest)
+include(ParseAndAddCatchTests)
+ParseAndAddCatchTests(foo)
+```
+
+
+#### Customization
+
+`ParseAndAddCatchTests` provides some customization points:
+* `PARSE_CATCH_TESTS_VERBOSE` -- When `ON`, the script prints debug
+messages. Defaults to `OFF`.
+* `PARSE_CATCH_TESTS_NO_HIDDEN_TESTS` -- When `ON`, hidden tests (tests
+tagged with either of `[.]` or `[.foo]`) will not be registered.
+Defaults to `OFF`.
+* `PARSE_CATCH_TESTS_ADD_FIXTURE_IN_TEST_NAME` -- When `ON`, adds fixture
+class name to the test name in CTest. Defaults to `ON`.
+* `PARSE_CATCH_TESTS_ADD_TARGET_IN_TEST_NAME` -- When `ON`, adds target
+name to the test name in CTest. Defaults to `ON`.
+* `PARSE_CATCH_TESTS_ADD_TO_CONFIGURE_DEPENDS` -- When `ON`, adds test
+file to `CMAKE_CONFIGURE_DEPENDS`. This means that the CMake configuration
+step will be re-ran when the test files change, letting new tests be
+automatically discovered. Defaults to `OFF`.
+
+
+Optionally, one can specify a launching command to run tests by setting the
+variable `OptionalCatchTestLauncher` before calling `ParseAndAddCatchTests`. For
+instance to run some tests using `MPI` and other sequentially, one can write
+```cmake
+set(OptionalCatchTestLauncher ${MPIEXEC} ${MPIEXEC_NUMPROC_FLAG} ${NUMPROC})
+ParseAndAddCatchTests(mpi_foo)
+unset(OptionalCatchTestLauncher)
+ParseAndAddCatchTests(bar)
+```
+
+
+### `CatchShardTests.cmake`
+
+> `CatchShardTests.cmake` was introduced in Catch2 3.1.0.
+
+`CatchShardTests.cmake` provides a function
+`catch_add_sharded_tests(TEST_BINARY)` that splits tests from `TEST_BINARY`
+into multiple shards. The tests in each shard and their order is randomized,
+and the seed changes every invocation of CTest.
+
+Currently there are 3 customization points for this script:
+
+ * SHARD_COUNT - number of shards to split target's tests into
+ * REPORTER    - reporter spec to use for tests
+ * TEST_SPEC   - test spec used for filtering tests
+
+Example usage:
+
+```
+include(CatchShardTests)
+
+catch_add_sharded_tests(foo-tests
+  SHARD_COUNT 4
+  REPORTER "xml::out=-"
+  TEST_SPEC "A"
+)
+
+catch_add_sharded_tests(tests
+  SHARD_COUNT 8
+  REPORTER "xml::out=-"
+  TEST_SPEC "B"
+)
+```
+
+This registers total of 12 CTest tests (4 + 8 shards) to run shards
+from `foo-tests` test binary, filtered by a test spec.
+
+_Note that this script is currently a proof-of-concept for reseeding
+shards per CTest run, and thus does not support (nor does it currently
+aim to support) all customization points from
+[`catch_discover_tests`](#catch_discover_tests)._
+
+
+## CMake project options
+
+Catch2's CMake project also provides some options for other projects
+that consume it. These are:
+
+* `BUILD_TESTING` -- When `ON` and the project is not used as a subproject,
+Catch2's test binary will be built. Defaults to `ON`.
+* `CATCH_INSTALL_DOCS` -- When `ON`, Catch2's documentation will be
+included in the installation. Defaults to `ON`.
+* `CATCH_INSTALL_EXTRAS` -- When `ON`, Catch2's extras folder (the CMake
+scripts mentioned above, debugger helpers) will be included in the
+installation. Defaults to `ON`.
+* `CATCH_DEVELOPMENT_BUILD` -- When `ON`, configures the build for development
+of Catch2. This means enabling test projects, warnings and so on.
+Defaults to `OFF`.
+
+
+Enabling `CATCH_DEVELOPMENT_BUILD` also enables further configuration
+customization options:
+
+* `CATCH_BUILD_TESTING` -- When `ON`, Catch2's SelfTest project will be
+built. Defaults to `ON`. Note that Catch2 also obeys `BUILD_TESTING` CMake
+variable, so _both_ of them need to be `ON` for the SelfTest to be built,
+and either of them can be set to `OFF` to disable building SelfTest.
+* `CATCH_BUILD_EXAMPLES` -- When `ON`, Catch2's usage examples will be
+built. Defaults to `OFF`.
+* `CATCH_BUILD_EXTRA_TESTS` -- When `ON`, Catch2's extra tests will be
+built. Defaults to `OFF`.
+* `CATCH_BUILD_FUZZERS` -- When `ON`, Catch2 fuzzing entry points will
+be built. Defaults to `OFF`.
+* `CATCH_ENABLE_WERROR` -- When `ON`, adds `-Werror` or equivalent flag
+to the compilation. Defaults to `ON`.
+* `CATCH_BUILD_SURROGATES` -- When `ON`, each header in Catch2 will be
+compiled separately to ensure that they are self-sufficient.
+Defaults to `OFF`.
+
+
+## `CATCH_CONFIG_*` customization options in CMake
+
+> CMake support for `CATCH_CONFIG_*` options was introduced in Catch2 3.0.1
+
+Due to the new separate compilation model, all the options from the
+[Compile-time configuration docs](configuration.md#top) can also be set
+through Catch2's CMake. To set them, define the option you want as `ON`,
+e.g. `-DCATCH_CONFIG_NOSTDOUT=ON`.
+
+Note that setting the option to `OFF` doesn't disable it. To force disable
+an option, you need to set the `_NO_` form of it to `ON`, e.g.
+`-DCATCH_CONFIG_NO_COLOUR_WIN32=ON`.
+
+
+To summarize the configuration option behaviour with an example:
+
+| `-DCATCH_CONFIG_COLOUR_WIN32` | `-DCATCH_CONFIG_NO_COLOUR_WIN32` |      Result |
+|-------------------------------|----------------------------------|-------------|
+|                          `ON` |                             `ON` |       error |
+|                          `ON` |                            `OFF` |    force-on |
+|                         `OFF` |                             `ON` |   force-off |
+|                         `OFF` |                            `OFF` | auto-detect |
+
+
+
+## Installing Catch2 from git repository
+
+If you cannot install Catch2 from a package manager (e.g. Ubuntu 16.04
+provides catch only in version 1.2.0) you might want to install it from
+the repository instead. Assuming you have enough rights, you can just
+install it to the default location, like so:
+```
+$ git clone https://github.com/catchorg/Catch2.git
+$ cd Catch2
+$ cmake -Bbuild -H. -DBUILD_TESTING=OFF
+$ sudo cmake --build build/ --target install
+```
+
+If you do not have superuser rights, you will also need to specify
+[CMAKE_INSTALL_PREFIX](https://cmake.org/cmake/help/latest/variable/CMAKE_INSTALL_PREFIX.html)
+when configuring the build, and then modify your calls to
+[find_package](https://cmake.org/cmake/help/latest/command/find_package.html)
+accordingly.
+
+## Installing Catch2 from vcpkg
+
+Alternatively, you can build and install Catch2 using [vcpkg](https://github.com/microsoft/vcpkg/) dependency manager:
+```
+git clone https://github.com/Microsoft/vcpkg.git
+cd vcpkg
+./bootstrap-vcpkg.sh
+./vcpkg integrate install
+./vcpkg install catch2
+```
+
+The catch2 port in vcpkg is kept up to date by microsoft team members and community contributors.
+If the version is out of date, please [create an issue or pull request](https://github.com/Microsoft/vcpkg) on the vcpkg repository.
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/command-line.md

@@ -0,0 +1,585 @@
+<a id="top"></a>
+# Command line
+
+**Contents**<br>
+[Specifying which tests to run](#specifying-which-tests-to-run)<br>
+[Choosing a reporter to use](#choosing-a-reporter-to-use)<br>
+[Breaking into the debugger](#breaking-into-the-debugger)<br>
+[Showing results for successful tests](#showing-results-for-successful-tests)<br>
+[Aborting after a certain number of failures](#aborting-after-a-certain-number-of-failures)<br>
+[Listing available tests, tags or reporters](#listing-available-tests-tags-or-reporters)<br>
+[Sending output to a file](#sending-output-to-a-file)<br>
+[Naming a test run](#naming-a-test-run)<br>
+[Eliding assertions expected to throw](#eliding-assertions-expected-to-throw)<br>
+[Make whitespace visible](#make-whitespace-visible)<br>
+[Warnings](#warnings)<br>
+[Reporting timings](#reporting-timings)<br>
+[Load test names to run from a file](#load-test-names-to-run-from-a-file)<br>
+[Specify the order test cases are run](#specify-the-order-test-cases-are-run)<br>
+[Specify a seed for the Random Number Generator](#specify-a-seed-for-the-random-number-generator)<br>
+[Identify framework and version according to the libIdentify standard](#identify-framework-and-version-according-to-the-libidentify-standard)<br>
+[Wait for key before continuing](#wait-for-key-before-continuing)<br>
+[Skip all benchmarks](#skip-all-benchmarks)<br>
+[Specify the number of benchmark samples to collect](#specify-the-number-of-benchmark-samples-to-collect)<br>
+[Specify the number of resamples for bootstrapping](#specify-the-number-of-resamples-for-bootstrapping)<br>
+[Specify the confidence-interval for bootstrapping](#specify-the-confidence-interval-for-bootstrapping)<br>
+[Disable statistical analysis of collected benchmark samples](#disable-statistical-analysis-of-collected-benchmark-samples)<br>
+[Specify the amount of time in milliseconds spent on warming up each test](#specify-the-amount-of-time-in-milliseconds-spent-on-warming-up-each-test)<br>
+[Usage](#usage)<br>
+[Specify the section to run](#specify-the-section-to-run)<br>
+[Filenames as tags](#filenames-as-tags)<br>
+[Override output colouring](#override-output-colouring)<br>
+[Test Sharding](#test-sharding)<br>
+[Allow running the binary without tests](#allow-running-the-binary-without-tests)<br>
+[Output verbosity](#output-verbosity)<br>
+
+Catch works quite nicely without any command line options at all - but for those times when you want greater control the following options are available.
+Click one of the following links to take you straight to that option - or scroll on to browse the available options.
+
+<a href="#specifying-which-tests-to-run">               `    <test-spec> ...`</a><br />
+<a href="#usage">                                       `    -h, -?, --help`</a><br />
+<a href="#showing-results-for-successful-tests">        `    -s, --success`</a><br />
+<a href="#breaking-into-the-debugger">                  `    -b, --break`</a><br />
+<a href="#eliding-assertions-expected-to-throw">        `    -e, --nothrow`</a><br />
+<a href="#invisibles">                                  `    -i, --invisibles`</a><br />
+<a href="#sending-output-to-a-file">                    `    -o, --out`</a><br />
+<a href="#choosing-a-reporter-to-use">                  `    -r, --reporter`</a><br />
+<a href="#naming-a-test-run">                           `    -n, --name`</a><br />
+<a href="#aborting-after-a-certain-number-of-failures"> `    -a, --abort`</a><br />
+<a href="#aborting-after-a-certain-number-of-failures"> `    -x, --abortx`</a><br />
+<a href="#warnings">                                    `    -w, --warn`</a><br />
+<a href="#reporting-timings">                           `    -d, --durations`</a><br />
+<a href="#input-file">                                  `    -f, --input-file`</a><br />
+<a href="#run-section">                                 `    -c, --section`</a><br />
+<a href="#filenames-as-tags">                           `    -#, --filenames-as-tags`</a><br />
+
+
+</br>
+
+<a href="#listing-available-tests-tags-or-reporters">   `    --list-tests`</a><br />
+<a href="#listing-available-tests-tags-or-reporters">   `    --list-tags`</a><br />
+<a href="#listing-available-tests-tags-or-reporters">   `    --list-reporters`</a><br />
+<a href="#listing-available-tests-tags-or-reporters">   `    --list-listeners`</a><br />
+<a href="#order">                                       `    --order`</a><br />
+<a href="#rng-seed">                                    `    --rng-seed`</a><br />
+<a href="#libidentify">                                 `    --libidentify`</a><br />
+<a href="#wait-for-keypress">                           `    --wait-for-keypress`</a><br />
+<a href="#skip-benchmarks">                             `    --skip-benchmarks`</a><br />
+<a href="#benchmark-samples">                           `    --benchmark-samples`</a><br />
+<a href="#benchmark-resamples">                         `    --benchmark-resamples`</a><br />
+<a href="#benchmark-confidence-interval">               `    --benchmark-confidence-interval`</a><br />
+<a href="#benchmark-no-analysis">                       `    --benchmark-no-analysis`</a><br />
+<a href="#benchmark-warmup-time">                       `    --benchmark-warmup-time`</a><br />
+<a href="#colour-mode">                                 `    --colour-mode`</a><br />
+<a href="#test-sharding">                               `    --shard-count`</a><br />
+<a href="#test-sharding">                               `    --shard-index`</a><br />
+<a href=#no-tests-override>                             `    --allow-running-no-tests`</a><br />
+<a href=#output-verbosity>                              `    --verbosity`</a><br />
+
+</br>
+
+
+
+<a id="specifying-which-tests-to-run"></a>
+## Specifying which tests to run
+
+<pre>&lt;test-spec> ...</pre>
+
+Test cases, wildcarded test cases, tags and tag expressions are all passed directly as arguments. Tags are distinguished by being enclosed in square brackets.
+
+If no test specs are supplied then all test cases, except "hidden" tests, are run.
+A test is hidden by giving it any tag starting with (or just) a period (```.```) - or, in the deprecated case, tagged ```[hide]``` or given name starting with `'./'`. To specify hidden tests from the command line ```[.]``` or ```[hide]``` can be used *regardless of how they were declared*.
+
+Specs must be enclosed in quotes if they contain spaces. If they do not contain spaces the quotes are optional.
+
+Wildcards consist of the `*` character at the beginning and/or end of test case names and can substitute for any number of any characters (including none).
+
+Test specs are case insensitive.
+
+If a spec is prefixed with `exclude:` or the `~` character then the pattern matches an exclusion. This means that tests matching the pattern are excluded from the set - even if a prior inclusion spec included them. Subsequent inclusion specs will take precedence, however.
+Inclusions and exclusions are evaluated in left-to-right order.
+
+Test case examples:
+
+```
+thisTestOnly            Matches the test case called, 'thisTestOnly'
+"this test only"        Matches the test case called, 'this test only'
+these*                  Matches all cases starting with 'these'
+exclude:notThis         Matches all tests except, 'notThis'
+~notThis                Matches all tests except, 'notThis'
+~*private*              Matches all tests except those that contain 'private'
+a* ~ab* abc             Matches all tests that start with 'a', except those that
+                        start with 'ab', except 'abc', which is included
+~[tag1]                 Matches all tests except those tagged with '[tag1]'
+-# [#somefile]          Matches all tests from the file 'somefile.cpp'
+```
+
+Names within square brackets are interpreted as tags.
+A series of tags form an AND expression whereas a comma-separated sequence forms an OR expression. e.g.:
+
+<pre>[one][two],[three]</pre>
+This matches all tests tagged `[one]` and `[two]`, as well as all tests tagged `[three]`
+
+Test names containing special characters, such as `,` or `[` can specify them on the command line using `\`.
+`\` also escapes itself.
+
+<a id="choosing-a-reporter-to-use"></a>
+## Choosing a reporter to use
+
+<pre>-r, --reporter &lt;reporter[::key=value]*&gt;</pre>
+
+Reporters are how the output from Catch2 (results of assertions, tests,
+benchmarks and so on) is formatted and written out. The default reporter
+is called the "Console" reporter and is intended to provide relatively
+verbose and human-friendly output.
+
+Reporters are also individually configurable. To pass configuration options
+to the reporter, you append `::key=value` to the reporter specification
+as many times as you want, e.g. `--reporter xml::out=someFile.xml`.
+
+The keys must either be prefixed by "X", in which case they are not parsed
+by Catch2 and are only passed down to the reporter, or one of options
+hardcoded into Catch2. Currently there are only 2,
+["out"](#sending-output-to-a-file), and ["colour-mode"](#colour-mode).
+
+_Note that the reporter might still check the X-prefixed options for
+validity, and throw an error if they are wrong._
+
+> Support for passing arguments to reporters through the `-r`, `--reporter` flag was introduced in Catch2 3.0.1
+
+There are multiple built-in reporters, you can see what they do by using the
+[`--list-reporter`](command-line.md#listing-available-tests-tags-or-reporters)
+flag. If you need a reporter providing custom format outside of the already
+provided ones, look at the ["write your own reporter" part of the reporter
+documentation](reporters.md#writing-your-own-reporter).
+
+This option may be passed multiple times to use multiple (different)
+reporters  at the same time. See the [reporter documentation](reporters.md#multiple-reporters)
+for details on what the resulting behaviour is. Also note that at most one
+reporter can be provided without the output-file part of reporter spec.
+This reporter will use the "default" output destination, based on
+the [`-o`, `--out`](#sending-output-to-a-file) option.
+
+> Support for using multiple different reporters at the same time was [introduced](https://github.com/catchorg/Catch2/pull/2183) in Catch2 3.0.1
+
+
+_Note: There is currently no way to escape `::` in the reporter spec,
+and thus the reporter names, or configuration keys and values, cannot
+contain `::`. As `::` in paths is relatively obscure (unlike ':'), we do
+not consider this an issue._
+
+
+<a id="breaking-into-the-debugger"></a>
+## Breaking into the debugger
+<pre>-b, --break</pre>
+
+Under most debuggers Catch2 is capable of automatically breaking on a test
+failure. This allows the user to see the current state of the test during
+failure.
+
+<a id="showing-results-for-successful-tests"></a>
+## Showing results for successful tests
+<pre>-s, --success</pre>
+
+Usually you only want to see reporting for failed tests. Sometimes it's useful to see *all* the output (especially when you don't trust that that test you just added worked first time!).
+To see successful, as well as failing, test results just pass this option. Note that each reporter may treat this option differently. The Junit reporter, for example, logs all results regardless.
+
+<a id="aborting-after-a-certain-number-of-failures"></a>
+## Aborting after a certain number of failures
+<pre>-a, --abort
+-x, --abortx [&lt;failure threshold>]
+</pre>
+
+If a ```REQUIRE``` assertion fails the test case aborts, but subsequent test cases are still run.
+If a ```CHECK``` assertion fails even the current test case is not aborted.
+
+Sometimes this results in a flood of failure messages and you'd rather just see the first few. Specifying ```-a``` or ```--abort``` on its own will abort the whole test run on the first failed assertion of any kind. Use ```-x``` or ```--abortx``` followed by a number to abort after that number of assertion failures.
+
+<a id="listing-available-tests-tags-or-reporters"></a>
+## Listing available tests, tags or reporters
+```
+--list-tests
+--list-tags
+--list-reporters
+--list-listeners
+```
+
+> The `--list*` options became customizable through reporters in Catch2 3.0.1
+
+> The `--list-listeners` option was added in Catch2 3.0.1
+
+`--list-tests` lists all registered tests matching specified test spec.
+Usually this listing also includes tags, and potentially also other
+information, like source location, based on verbosity and reporter's design.
+
+`--list-tags` lists all tags from registered tests matching specified test
+spec. Usually this also includes number of tests cases they match and
+similar information.
+
+`--list-reporters` lists all available reporters and their descriptions.
+
+`--list-listeners` lists all registered listeners and their descriptions.
+
+The [`--verbosity` argument](#output-verbosity) modifies the level of detail provided by the default `--list*` options
+as follows:
+
+| Option             | `normal` (default)              | `quiet`             | `high`                                  |
+|--------------------|---------------------------------|---------------------|-----------------------------------------|
+| `--list-tests`     | Test names and tags             | Test names only     | Same as `normal`, plus source code line |
+| `--list-tags`      | Tags and counts                 | Same as `normal`    | Same as `normal`                        |
+| `--list-reporters` | Reporter names and descriptions | Reporter names only | Same as `normal`                        |
+| `--list-listeners` | Listener names and descriptions | Same as `normal`    | Same as `normal`                        |
+
+<a id="sending-output-to-a-file"></a>
+## Sending output to a file
+<pre>-o, --out &lt;filename&gt;
+</pre>
+
+Use this option to send all output to a file, instead of stdout. You can
+use `-` as the filename to explicitly send the output to stdout (this is
+useful e.g. when using multiple reporters).
+
+> Support for `-` as the filename was introduced in Catch2 3.0.1
+
+Filenames starting with "%" (percent symbol) are reserved by Catch2 for
+meta purposes, e.g. using `%debug` as the filename opens stream that
+writes to platform specific debugging/logging mechanism.
+
+Catch2 currently recognizes 3 meta streams:
+
+* `%debug` - writes to platform specific debugging/logging output
+* `%stdout` - writes to stdout
+* `%stderr` - writes to stderr
+
+> Support for `%stdout` and `%stderr` was introduced in Catch2 3.0.1
+
+
+<a id="naming-a-test-run"></a>
+## Naming a test run
+<pre>-n, --name &lt;name for test run></pre>
+
+If a name is supplied it will be used by the reporter to provide an overall name for the test run. This can be useful if you are sending to a file, for example, and need to distinguish different test runs - either from different Catch executables or runs of the same executable with different options. If not supplied the name is defaulted to the name of the executable.
+
+<a id="eliding-assertions-expected-to-throw"></a>
+## Eliding assertions expected to throw
+<pre>-e, --nothrow</pre>
+
+Skips all assertions that test that an exception is thrown, e.g. ```REQUIRE_THROWS```.
+
+These can be a nuisance in certain debugging environments that may break when exceptions are thrown (while this is usually optional for handled exceptions, it can be useful to have enabled if you are trying to track down something unexpected).
+
+Sometimes exceptions are expected outside of one of the assertions that tests for them (perhaps thrown and caught within the code-under-test). The whole test case can be skipped when using ```-e``` by marking it with the ```[!throws]``` tag.
+
+When running with this option any throw checking assertions are skipped so as not to contribute additional noise. Be careful if this affects the behaviour of subsequent tests.
+
+<a id="invisibles"></a>
+## Make whitespace visible
+<pre>-i, --invisibles</pre>
+
+If a string comparison fails due to differences in whitespace - especially leading or trailing whitespace - it can be hard to see what's going on.
+This option transforms tabs and newline characters into ```\t``` and ```\n``` respectively when printing.
+
+<a id="warnings"></a>
+## Warnings
+<pre>-w, --warn &lt;warning name></pre>
+
+You can think of Catch2's warnings as the equivalent of `-Werror` (`/WX`)
+flag for C++ compilers. It turns some suspicious occurrences, like a section
+without assertions, into errors. Because these might be intended, warnings
+are not enabled by default, but user can opt in.
+
+You can enable multiple warnings at the same time.
+
+There are currently two warnings implemented:
+
+```
+    NoAssertions        // Fail test case / leaf section if no assertions
+                        // (e.g. `REQUIRE`) is encountered.
+    UnmatchedTestSpec   // Fail test run if any of the CLI test specs did
+                        // not match any tests.
+```
+
+> `UnmatchedTestSpec` was introduced in Catch2 3.0.1.
+
+
+<a id="reporting-timings"></a>
+## Reporting timings
+<pre>-d, --durations &lt;yes/no></pre>
+
+When set to ```yes``` Catch will report the duration of each test case, in milliseconds. Note that it does this regardless of whether a test case passes or fails. Note, also, the certain reporters (e.g. Junit) always report test case durations regardless of this option being set or not.
+
+<pre>-D, --min-duration &lt;value></pre>
+
+> `--min-duration` was [introduced](https://github.com/catchorg/Catch2/pull/1910) in Catch2 2.13.0
+
+When set, Catch will report the duration of each test case that took more
+than &lt;value> seconds, in milliseconds. This option is overridden by both
+`-d yes` and `-d no`, so that either all durations are reported, or none
+are.
+
+
+<a id="input-file"></a>
+## Load test names to run from a file
+<pre>-f, --input-file &lt;filename></pre>
+
+Provide the name of a file that contains a list of test case names,
+one per line. Blank lines are skipped.
+
+A useful way to generate an initial instance of this file is to combine
+the [`--list-tests`](#listing-available-tests-tags-or-reporters) flag with
+the [`--verbosity quiet`](#output-verbosity) option. You can also
+use test specs to filter this list down to what you want first.
+
+
+<a id="order"></a>
+## Specify the order test cases are run
+<pre>--order &lt;decl|lex|rand&gt;</pre>
+
+Test cases are ordered one of three ways:
+
+### decl
+Declaration order (this is the default order if no --order argument is provided).
+Tests in the same translation unit are sorted using their declaration orders,
+different TUs are sorted in an implementation (linking) dependent order.
+
+
+### lex
+Lexicographic order. Tests are sorted by their name, their tags are ignored.
+
+
+### rand
+
+Randomly ordered. The order is dependent on Catch2's random seed (see
+[`--rng-seed`](#rng-seed)), and is subset invariant. What this means
+is that as long as the random seed is fixed, running only some tests
+(e.g. via tag) does not change their relative order.
+
+> The subset stability was introduced in Catch2 v2.12.0
+
+Since the random order was made subset stable, we promise that given
+the same random seed, the order of test cases will be the same across
+different platforms, as long as the tests were compiled against identical
+version of Catch2. We reserve the right to change the relative order
+of tests cases between Catch2 versions, but it is unlikely to happen often.
+
+
+<a id="rng-seed"></a>
+## Specify a seed for the Random Number Generator
+<pre>--rng-seed &lt;'time'|'random-device'|number&gt;</pre>
+
+Sets the seed for random number generators used by Catch2. These are used
+e.g. to shuffle tests when user asks for tests to be in random order.
+
+Using `time` as the argument asks Catch2 generate the seed through call
+to `std::time(nullptr)`. This provides very weak randomness and multiple
+runs of the binary can generate the same seed if they are started close
+to each other.
+
+Using `random-device` asks for `std::random_device` to be used instead.
+If your implementation provides working `std::random_device`, it should
+be preferred to using `time`. Catch2 uses `std::random_device` by default.
+
+
+<a id="libidentify"></a>
+## Identify framework and version according to the libIdentify standard
+<pre>--libidentify</pre>
+
+See [The LibIdentify repo for more information and examples](https://github.com/janwilmans/LibIdentify).
+
+<a id="wait-for-keypress"></a>
+## Wait for key before continuing
+<pre>--wait-for-keypress &lt;never|start|exit|both&gt;</pre>
+
+Will cause the executable to print a message and wait until the return/ enter key is pressed before continuing -
+either before running any tests, after running all tests - or both, depending on the argument.
+
+<a id="skip-benchmarks"></a>
+## Skip all benchmarks
+<pre>--skip-benchmarks</pre>
+
+> [Introduced](https://github.com/catchorg/Catch2/issues/2408) in Catch2 3.0.1.
+
+This flag tells Catch2 to skip running all benchmarks. Benchmarks in this
+case mean code blocks in `BENCHMARK` and `BENCHMARK_ADVANCED` macros, not
+test cases with the `[!benchmark]` tag.
+
+<a id="benchmark-samples"></a>
+## Specify the number of benchmark samples to collect
+<pre>--benchmark-samples &lt;# of samples&gt;</pre>
+
+> [Introduced](https://github.com/catchorg/Catch2/issues/1616) in Catch2 2.9.0.
+
+When running benchmarks a number of "samples" is collected. This is the base data for later statistical analysis.
+Per sample a clock resolution dependent number of iterations of the user code is run, which is independent of the number of samples. Defaults to 100.
+
+<a id="benchmark-resamples"></a>
+## Specify the number of resamples for bootstrapping
+<pre>--benchmark-resamples &lt;# of resamples&gt;</pre>
+
+> [Introduced](https://github.com/catchorg/Catch2/issues/1616) in Catch2 2.9.0.
+
+After the measurements are performed, statistical [bootstrapping] is performed
+on the samples. The number of resamples for that bootstrapping is configurable
+but defaults to 100000. Due to the bootstrapping it is possible to give
+estimates for the mean and standard deviation. The estimates come with a lower
+bound and an upper bound, and the confidence interval (which is configurable but
+defaults to 95%).
+
+ [bootstrapping]: http://en.wikipedia.org/wiki/Bootstrapping_%28statistics%29
+
+<a id="benchmark-confidence-interval"></a>
+## Specify the confidence-interval for bootstrapping
+<pre>--benchmark-confidence-interval &lt;confidence-interval&gt;</pre>
+
+> [Introduced](https://github.com/catchorg/Catch2/issues/1616) in Catch2 2.9.0.
+
+The confidence-interval is used for statistical bootstrapping on the samples to
+calculate the upper and lower bounds of mean and standard deviation.
+Must be between 0 and 1 and defaults to 0.95.
+
+<a id="benchmark-no-analysis"></a>
+## Disable statistical analysis of collected benchmark samples
+<pre>--benchmark-no-analysis</pre>
+
+> [Introduced](https://github.com/catchorg/Catch2/issues/1616) in Catch2 2.9.0.
+
+When this flag is specified no bootstrapping or any other statistical analysis is performed.
+Instead the user code is only measured and the plain mean from the samples is reported.
+
+<a id="benchmark-warmup-time"></a>
+## Specify the amount of time in milliseconds spent on warming up each test
+<pre>--benchmark-warmup-time</pre>
+
+> [Introduced](https://github.com/catchorg/Catch2/pull/1844) in Catch2 2.11.2.
+
+Configure the amount of time spent warming up each test.
+
+<a id="usage"></a>
+## Usage
+<pre>-h, -?, --help</pre>
+
+Prints the command line arguments to stdout
+
+
+<a id="run-section"></a>
+## Specify the section to run
+<pre>-c, --section &lt;section name&gt;</pre>
+
+To limit execution to a specific section within a test case, use this option one or more times.
+To narrow to sub-sections use multiple instances, where each subsequent instance specifies a deeper nesting level.
+
+E.g. if you have:
+
+<pre>
+TEST_CASE( "Test" ) {
+  SECTION( "sa" ) {
+    SECTION( "sb" ) {
+      /*...*/
+    }
+    SECTION( "sc" ) {
+      /*...*/
+    }
+  }
+  SECTION( "sd" ) {
+    /*...*/
+  }
+}
+</pre>
+
+Then you can run `sb` with:
+<pre>./MyExe Test -c sa -c sb</pre>
+
+Or run just `sd` with:
+<pre>./MyExe Test -c sd</pre>
+
+To run all of `sa`, including `sb` and `sc` use:
+<pre>./MyExe Test -c sa</pre>
+
+There are some limitations of this feature to be aware of:
+- Code outside of sections being skipped will still be executed - e.g. any set-up code in the TEST_CASE before the
+start of the first section.</br>
+- At time of writing, wildcards are not supported in section names.
+- If you specify a section without narrowing to a test case first then all test cases will be executed
+(but only matching sections within them).
+
+
+<a id="filenames-as-tags"></a>
+## Filenames as tags
+<pre>-#, --filenames-as-tags</pre>
+
+When this option is used then every test is given an additional tag which is formed of the unqualified
+filename it is found in, with any extension stripped, prefixed with the `#` character.
+
+So, for example,  tests within the file `~\Dev\MyProject\Ferrets.cpp` would be tagged `[#Ferrets]`.
+
+<a id="colour-mode"></a>
+## Override output colouring
+<pre>--colour-mode &lt;ansi|win32|none|default&gt;</pre>
+
+> The `--colour-mode` option replaced the old `--colour` option in Catch2 3.0.1
+
+
+Catch2 support two different ways of colouring terminal output, and by
+default it attempts to make a good guess on which implementation to use
+(and whether to even use it, e.g. Catch2 tries to avoid writing colour
+codes when writing the results into a file).
+
+`--colour-mode` allows the user to explicitly select what happens.
+
+* `--colour-mode ansi` tells Catch2 to always use ANSI colour codes, even
+when writing to a file
+* `--colour-mode win32` tells Catch2 to use colour implementation based
+  on Win32 terminal API
+* `--colour-mode none` tells Catch2 to disable colours completely
+* `--colour-mode default` lets Catch2 decide
+
+`--colour-mode default` is the default setting.
+
+
+<a id="test-sharding"></a>
+## Test Sharding
+<pre>--shard-count <#number of shards>, --shard-index <#shard index to run></pre>
+
+> [Introduced](https://github.com/catchorg/Catch2/pull/2257) in Catch2 3.0.1.
+
+When `--shard-count <#number of shards>` is used, the tests to execute
+will be split evenly in to the given number of sets, identified by indices
+starting at 0. The tests in the set given by
+`--shard-index <#shard index to run>` will be executed. The default shard
+count is `1`, and the default index to run is `0`.
+
+_Shard index must be less than number of shards. As the name suggests,
+it is treated as an index of the shard to run._
+
+Sharding is useful when you want to split test execution across multiple
+processes, as is done with the [Bazel test sharding](https://docs.bazel.build/versions/main/test-encyclopedia.html#test-sharding).
+
+
+<a id="no-tests-override"></a>
+## Allow running the binary without tests
+<pre>--allow-running-no-tests</pre>
+
+> Introduced in Catch2 3.0.1.
+
+By default, Catch2 test binaries return non-0 exit code if no tests were
+run, e.g. if the binary was compiled with no tests, or the provided test
+spec matched no tests. This flag overrides that, so a test run with no
+tests still returns 0.
+
+## Output verbosity
+```
+-v, --verbosity <quiet|normal|high>
+```
+
+Changing verbosity might change how many details Catch2's reporters output.
+However, you should consider changing the verbosity level as a _suggestion_.
+Not all reporters support all verbosity levels, e.g. because the reporter's
+format cannot meaningfully change. In that case, the verbosity level is
+ignored.
+
+Verbosity defaults to _normal_.
+
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/commercial-users.md

@@ -0,0 +1,23 @@
+<a id="top"></a>
+# Commercial users of Catch2
+
+Catch2 is also widely used in proprietary code bases. This page contains
+some of them that are willing to share this information.
+
+If you want to add your organisation, please check that there is no issue
+with you sharing this fact.
+
+ - Bloomberg
+ - [Bloomlife](https://bloomlife.com)
+ - [Inscopix Inc.](https://www.inscopix.com/)
+ - Locksley.CZ
+ - [Makimo](https://makimo.pl/)
+ - NASA
+ - [Nexus Software Systems](https://nexwebsites.com)
+ - [UX3D](https://ux3d.io)
+ - [King](https://king.com)
+
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/comparing-floating-point-numbers.md

@@ -0,0 +1,192 @@
+<a id="top"></a>
+# Comparing floating point numbers with Catch2
+
+If you are not deeply familiar with them, floating point numbers can be
+unintuitive. This also applies to comparing floating point numbers for
+(in)equality.
+
+This page assumes that you have some understanding of both FP, and the
+meaning of different kinds of comparisons, and only goes over what
+functionality Catch2 provides to help you with comparing floating point
+numbers. If you do not have this understanding, we recommend that you first
+study up on floating point numbers and their comparisons, e.g. by [reading
+this blog post](https://codingnest.com/the-little-things-comparing-floating-point-numbers/).
+
+
+## Floating point matchers
+
+```
+#include <catch2/matchers/catch_matchers_floating_point.hpp>
+```
+
+[Matchers](matchers.md#top) are the preferred way of comparing floating
+point numbers in Catch2. We provide 3 of them:
+
+* `WithinAbs(double target, double margin)`,
+* `WithinRel(FloatingPoint target, FloatingPoint eps)`, and
+* `WithinULP(FloatingPoint target, uint64_t maxUlpDiff)`.
+
+> `WithinRel` matcher was introduced in Catch2 2.10.0
+
+As with all matchers, you can combine multiple floating point matchers
+in a single assertion. For example, to check that some computation matches
+a known good value within 0.1% or is close enough (no different to 5
+decimal places) to zero, we would write this assertion:
+
+```cpp
+    REQUIRE_THAT( computation(input),
+        Catch::Matchers::WithinRel(expected, 0.001)
+     || Catch::Matchers::WithinAbs(0, 0.000001) );
+```
+
+
+### WithinAbs
+
+`WithinAbs` creates a matcher that accepts floating point numbers whose
+difference with `target` is less-or-equal to the `margin`. Since `float`
+can be converted to `double` without losing precision, only `double`
+overload exists.
+
+```cpp
+REQUIRE_THAT(1.0, WithinAbs(1.2, 0.2));
+REQUIRE_THAT(0.f, !WithinAbs(1.0, 0.5));
+// Notice that infinity == infinity for WithinAbs
+REQUIRE_THAT(INFINITY, WithinAbs(INFINITY, 0));
+```
+
+
+### WithinRel
+
+`WithinRel` creates a matcher that accepts floating point numbers that
+are _approximately equal_ to the `target` with a tolerance of `eps.`
+Specifically, it matches if
+`|arg - target| <= eps * max(|arg|, |target|)` holds. If you do not
+specify `eps`, `std::numeric_limits<FloatingPoint>::epsilon * 100`
+is used as the default.
+
+```cpp
+// Notice that WithinRel comparison is symmetric, unlike Approx's.
+REQUIRE_THAT(1.0, WithinRel(1.1, 0.1));
+REQUIRE_THAT(1.1, WithinRel(1.0, 0.1));
+// Notice that inifnity == infinity for WithinRel
+REQUIRE_THAT(INFINITY, WithinRel(INFINITY));
+```
+
+
+### WithinULP
+
+`WithinULP` creates a matcher that accepts floating point numbers that
+are no more than `maxUlpDiff`
+[ULPs](https://en.wikipedia.org/wiki/Unit_in_the_last_place)
+away from the `target` value. The short version of what this means
+is that there is no more than `maxUlpDiff - 1` representable floating
+point numbers between the argument for matching and the `target` value.
+
+When using the ULP matcher in Catch2, it is important to keep in mind
+that Catch2 interprets ULP distance slightly differently than
+e.g. `std::nextafter` does.
+
+Catch2's ULP calculation obeys these relations:
+  * `ulpDistance(-x, x) == 2 * ulpDistance(x, 0)`
+  * `ulpDistance(-0, 0) == 0` (due to the above)
+  * `ulpDistance(DBL_MAX, INFINITY) == 1`
+  * `ulpDistancE(NaN, x) == infinity`
+
+
+**Important**: The WithinULP matcher requires the platform to use the
+[IEEE-754](https://en.wikipedia.org/wiki/IEEE_754) representation for
+floating point numbers.
+
+```cpp
+REQUIRE_THAT( -0.f, WithinULP( 0.f, 0 ) );
+```
+
+
+## `Approx`
+
+```
+#include <catch2/catch_approx.hpp>
+```
+
+**We strongly recommend against using `Approx` when writing new code.**
+You should be using floating point matchers instead.
+
+Catch2 provides one more way to handle floating point comparisons. It is
+`Approx`, a special type with overloaded comparison operators, that can
+be used in standard assertions, e.g.
+
+```cpp
+REQUIRE(0.99999 == Catch::Approx(1));
+```
+
+`Approx` supports four comparison operators, `==`, `!=`, `<=`, `>=`, and can
+also be used with strong typedefs over `double`s. It can be used for both
+relative and margin comparisons by using its three customization points.
+Note that the semantics of this is always that of an _or_, so if either
+the relative or absolute margin comparison passes, then the whole comparison
+passes.
+
+The downside to `Approx` is that it has a couple of issues that we cannot
+fix without breaking backwards compatibility. Because Catch2 also provides
+complete set of matchers that implement different floating point comparison
+methods, `Approx` is left as-is, is considered deprecated, and should
+not be used in new code.
+
+The issues are
+  * All internal computation is done in `double`s, leading to slightly
+    different results if the inputs were floats.
+  * `Approx`'s relative margin comparison is not symmetric. This means
+    that `Approx( 10 ).epsilon(0.1) != 11.1` but `Approx( 11.1 ).epsilon(0.1) == 10`.
+  * By default, `Approx` only uses relative margin comparison. This means
+    that `Approx(0) == X` only passes for `X == 0`.
+
+
+### Approx details
+
+If you still want/need to know more about `Approx`, read on.
+
+Catch2 provides a UDL for `Approx`; `_a`. It resides in the `Catch::literals`
+namespace, and can be used like this:
+
+```cpp
+using namespace Catch::literals;
+REQUIRE( performComputation() == 2.1_a );
+```
+
+`Approx` has three customization points for the comparison:
+
+* **epsilon** - epsilon sets the coefficient by which a result
+can differ from `Approx`'s value before it is rejected.
+_Defaults to `std::numeric_limits<float>::epsilon()*100`._
+
+```cpp
+Approx target = Approx(100).epsilon(0.01);
+100.0 == target; // Obviously true
+200.0 == target; // Obviously still false
+100.5 == target; // True, because we set target to allow up to 1% difference
+```
+
+
+* **margin** - margin sets the absolute value by which
+a result can differ from `Approx`'s value before it is rejected.
+_Defaults to `0.0`._
+
+```cpp
+Approx target = Approx(100).margin(5);
+100.0 == target; // Obviously true
+200.0 == target; // Obviously still false
+104.0 == target; // True, because we set target to allow absolute difference of at most 5
+```
+
+* **scale** - scale is used to change the magnitude of `Approx` for the relative check.
+_By default, set to `0.0`._
+
+Scale could be useful if the computation leading to the result worked
+on a different scale than is used by the results. Approx's scale is added
+to Approx's value when computing the allowed relative margin from the
+Approx's value.
+
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/configuration.md

@@ -0,0 +1,269 @@
+<a id="top"></a>
+# Compile-time configuration
+
+**Contents**<br>
+[Prefixing Catch macros](#prefixing-catch-macros)<br>
+[Terminal colour](#terminal-colour)<br>
+[Console width](#console-width)<br>
+[stdout](#stdout)<br>
+[Fallback stringifier](#fallback-stringifier)<br>
+[Default reporter](#default-reporter)<br>
+[Bazel support](#bazel-support)<br>
+[C++11 toggles](#c11-toggles)<br>
+[C++17 toggles](#c17-toggles)<br>
+[Other toggles](#other-toggles)<br>
+[Enabling stringification](#enabling-stringification)<br>
+[Disabling exceptions](#disabling-exceptions)<br>
+[Overriding Catch's debug break (`-b`)](#overriding-catchs-debug-break--b)<br>
+
+Catch2 is designed to "just work" as much as possible, and most of the
+configuration options below are changed automatically during compilation,
+according to the detected environment. However, this detection can also
+be overridden by users, using macros documented below, and/or CMake options
+with the same name.
+
+
+## Prefixing Catch macros
+
+    CATCH_CONFIG_PREFIX_ALL
+
+To keep test code clean and uncluttered Catch uses short macro names (e.g. ```TEST_CASE``` and ```REQUIRE```). Occasionally these may conflict with identifiers from platform headers or the system under test. In this case the above identifier can be defined. This will cause all the Catch user macros to be prefixed with ```CATCH_``` (e.g. ```CATCH_TEST_CASE``` and ```CATCH_REQUIRE```).
+
+
+## Terminal colour
+
+    CATCH_CONFIG_COLOUR_WIN32     // Force enables compiling colouring impl based on Win32 console API
+    CATCH_CONFIG_NO_COLOUR_WIN32  // Force disables ...
+
+Yes, Catch2 uses the british spelling of colour.
+
+Catch2 attempts to autodetect whether the Win32 console colouring API,
+`SetConsoleTextAttribute`, is available, and if it is available it compiles
+in a console colouring implementation that uses it.
+
+This option can be used to override Catch2's autodetection and force the
+compilation either ON or OFF.
+
+
+## Console width
+
+    CATCH_CONFIG_CONSOLE_WIDTH = x // where x is a number
+
+Catch formats output intended for the console to fit within a fixed number of characters. This is especially important as indentation is used extensively and uncontrolled line wraps break this.
+By default a console width of 80 is assumed but this can be controlled by defining the above identifier to be a different value.
+
+## stdout
+
+    CATCH_CONFIG_NOSTDOUT
+
+To support platforms that do not provide `std::cout`, `std::cerr` and
+`std::clog`, Catch does not use them directly, but rather calls
+`Catch::cout`, `Catch::cerr` and `Catch::clog`. You can replace their
+implementation by defining `CATCH_CONFIG_NOSTDOUT` and implementing
+them yourself, their signatures are:
+
+    std::ostream& cout();
+    std::ostream& cerr();
+    std::ostream& clog();
+
+[You can see an example of replacing these functions here.](
+../examples/231-Cfg-OutputStreams.cpp)
+
+
+## Fallback stringifier
+
+By default, when Catch's stringification machinery has to stringify
+a type that does not specialize `StringMaker`, does not overload `operator<<`,
+is not an enumeration and is not a range, it uses `"{?}"`. This can be
+overridden by defining `CATCH_CONFIG_FALLBACK_STRINGIFIER` to name of a
+function that should perform the stringification instead.
+
+All types that do not provide `StringMaker` specialization or `operator<<`
+overload will be sent to this function (this includes enums and ranges).
+The provided function must return `std::string` and must accept any type,
+e.g. via overloading.
+
+_Note that if the provided function does not handle a type and this type
+requires to be stringified, the compilation will fail._
+
+
+## Default reporter
+
+Catch's default reporter can be changed by defining macro
+`CATCH_CONFIG_DEFAULT_REPORTER` to string literal naming the desired
+default reporter.
+
+This means that defining `CATCH_CONFIG_DEFAULT_REPORTER` to `"console"`
+is equivalent with the out-of-the-box experience.
+
+
+## Bazel support
+
+Compiling Catch2 with `CATCH_CONFIG_BAZEL_SUPPORT` force-enables Catch2's
+support for Bazel's environment variables (normally Catch2 looks for
+`BAZEL_TEST=1` env var first).
+
+This can be useful if you are using older versions of Bazel, that do not
+yet have `BAZEL_TEST` env var support.
+
+> `CATCH_CONFIG_BAZEL_SUPPORT` was [introduced](https://github.com/catchorg/Catch2/pull/2399) in Catch2 3.0.1.
+
+> `CATCH_CONFIG_BAZEL_SUPPORT` was [deprecated](https://github.com/catchorg/Catch2/pull/2459) in Catch2 3.1.0.
+
+
+## C++11 toggles
+
+    CATCH_CONFIG_CPP11_TO_STRING // Use `std::to_string`
+
+Because we support platforms whose standard library does not contain
+`std::to_string`, it is possible to force Catch to use a workaround
+based on `std::stringstream`. On platforms other than Android,
+the default is to use `std::to_string`. On Android, the default is to
+use the `stringstream` workaround. As always, it is possible to override
+Catch's selection, by defining either `CATCH_CONFIG_CPP11_TO_STRING` or
+`CATCH_CONFIG_NO_CPP11_TO_STRING`.
+
+
+## C++17 toggles
+
+    CATCH_CONFIG_CPP17_UNCAUGHT_EXCEPTIONS  // Override std::uncaught_exceptions (instead of std::uncaught_exception) support detection
+    CATCH_CONFIG_CPP17_STRING_VIEW          // Override std::string_view support detection (Catch provides a StringMaker specialization by default)
+    CATCH_CONFIG_CPP17_VARIANT              // Override std::variant support detection (checked by CATCH_CONFIG_ENABLE_VARIANT_STRINGMAKER)
+    CATCH_CONFIG_CPP17_OPTIONAL             // Override std::optional support detection (checked by CATCH_CONFIG_ENABLE_OPTIONAL_STRINGMAKER)
+    CATCH_CONFIG_CPP17_BYTE                 // Override std::byte support detection (Catch provides a StringMaker specialization by default)
+
+> `CATCH_CONFIG_CPP17_STRING_VIEW` was [introduced](https://github.com/catchorg/Catch2/issues/1376) in Catch2 2.4.1.
+
+Catch contains basic compiler/standard detection and attempts to use
+some C++17 features whenever appropriate. This automatic detection
+can be manually overridden in both directions, that is, a feature
+can be enabled by defining the macro in the table above, and disabled
+by using `_NO_` in the macro, e.g. `CATCH_CONFIG_NO_CPP17_UNCAUGHT_EXCEPTIONS`.
+
+
+## Other toggles
+
+    CATCH_CONFIG_COUNTER                    // Use __COUNTER__ to generate unique names for test cases
+    CATCH_CONFIG_WINDOWS_SEH                // Enable SEH handling on Windows
+    CATCH_CONFIG_FAST_COMPILE               // Sacrifices some (rather minor) features for compilation speed
+    CATCH_CONFIG_POSIX_SIGNALS              // Enable handling POSIX signals
+    CATCH_CONFIG_WINDOWS_CRTDBG             // Enable leak checking using Windows's CRT Debug Heap
+    CATCH_CONFIG_DISABLE_STRINGIFICATION    // Disable stringifying the original expression
+    CATCH_CONFIG_DISABLE                    // Disables assertions and test case registration
+    CATCH_CONFIG_WCHAR                      // Enables use of wchart_t
+    CATCH_CONFIG_EXPERIMENTAL_REDIRECT      // Enables the new (experimental) way of capturing stdout/stderr
+    CATCH_CONFIG_USE_ASYNC                  // Force parallel statistical processing of samples during benchmarking
+    CATCH_CONFIG_ANDROID_LOGWRITE           // Use android's logging system for debug output
+    CATCH_CONFIG_GLOBAL_NEXTAFTER           // Use nextafter{,f,l} instead of std::nextafter
+    CATCH_CONFIG_GETENV                     // System has a working `getenv`
+
+> [`CATCH_CONFIG_ANDROID_LOGWRITE`](https://github.com/catchorg/Catch2/issues/1743) and [`CATCH_CONFIG_GLOBAL_NEXTAFTER`](https://github.com/catchorg/Catch2/pull/1739) were introduced in Catch2 2.10.0
+
+> `CATCH_CONFIG_GETENV` was [introduced](https://github.com/catchorg/Catch2/pull/2562) in Catch2 3.2.0
+
+Currently Catch enables `CATCH_CONFIG_WINDOWS_SEH` only when compiled with MSVC, because some versions of MinGW do not have the necessary Win32 API support.
+
+`CATCH_CONFIG_POSIX_SIGNALS` is on by default, except when Catch is compiled under `Cygwin`, where it is disabled by default (but can be force-enabled by defining `CATCH_CONFIG_POSIX_SIGNALS`).
+
+`CATCH_CONFIG_GETENV` is on by default, except when Catch2 is compiled for
+platforms that lacks working `std::getenv` (currently Windows UWP and
+Playstation).
+
+`CATCH_CONFIG_WINDOWS_CRTDBG` is off by default. If enabled, Windows's
+CRT is used to check for memory leaks, and displays them after the tests
+finish running. This option only works when linking against the default
+main, and must be defined for the whole library build.
+
+`CATCH_CONFIG_WCHAR` is on by default, but can be disabled. Currently
+it is only used in support for DJGPP cross-compiler.
+
+With the exception of `CATCH_CONFIG_EXPERIMENTAL_REDIRECT`,
+these toggles can be disabled by using `_NO_` form of the toggle,
+e.g. `CATCH_CONFIG_NO_WINDOWS_SEH`.
+
+### `CATCH_CONFIG_FAST_COMPILE`
+This compile-time flag speeds up compilation of assertion macros by ~20%,
+by disabling the generation of assertion-local try-catch blocks for
+non-exception family of assertion macros ({`REQUIRE`,`CHECK`}{``,`_FALSE`, `_THAT`}).
+This disables translation of exceptions thrown under these assertions, but
+should not lead to false negatives.
+
+`CATCH_CONFIG_FAST_COMPILE` has to be either defined, or not defined,
+in all translation units that are linked into single test binary.
+
+### `CATCH_CONFIG_DISABLE_STRINGIFICATION`
+This toggle enables a workaround for VS 2017 bug. For details see [known limitations](limitations.md#visual-studio-2017----raw-string-literal-in-assert-fails-to-compile).
+
+### `CATCH_CONFIG_DISABLE`
+This toggle removes most of Catch from given file. This means that `TEST_CASE`s are not registered and assertions are turned into no-ops. Useful for keeping tests within implementation files (ie for functions with internal linkage), instead of in external files.
+
+This feature is considered experimental and might change at any point.
+
+_Inspired by Doctest's `DOCTEST_CONFIG_DISABLE`_
+
+
+## Enabling stringification
+
+By default, Catch does not stringify some types from the standard library. This is done to avoid dragging in various standard library headers by default. However, Catch does contain these and can be configured to provide them, using these macros:
+
+    CATCH_CONFIG_ENABLE_PAIR_STRINGMAKER     // Provide StringMaker specialization for std::pair
+    CATCH_CONFIG_ENABLE_TUPLE_STRINGMAKER    // Provide StringMaker specialization for std::tuple
+    CATCH_CONFIG_ENABLE_VARIANT_STRINGMAKER  // Provide StringMaker specialization for std::variant, std::monostate (on C++17)
+    CATCH_CONFIG_ENABLE_OPTIONAL_STRINGMAKER // Provide StringMaker specialization for std::optional (on C++17)
+    CATCH_CONFIG_ENABLE_ALL_STRINGMAKERS     // Defines all of the above
+
+> `CATCH_CONFIG_ENABLE_VARIANT_STRINGMAKER` was [introduced](https://github.com/catchorg/Catch2/issues/1380) in Catch2 2.4.1.
+
+> `CATCH_CONFIG_ENABLE_OPTIONAL_STRINGMAKER` was [introduced](https://github.com/catchorg/Catch2/issues/1510) in Catch2 2.6.0.
+
+## Disabling exceptions
+
+> Introduced in Catch2 2.4.0.
+
+By default, Catch2 uses exceptions to signal errors and to abort tests
+when an assertion from the `REQUIRE` family of assertions fails. We also
+provide an experimental support for disabling exceptions. Catch2 should
+automatically detect when it is compiled with exceptions disabled, but
+it can be forced to compile without exceptions by defining
+
+    CATCH_CONFIG_DISABLE_EXCEPTIONS
+
+Note that when using Catch2 without exceptions, there are 2 major
+limitations:
+
+1) If there is an error that would normally be signalled by an exception,
+the exception's message will instead be written to `Catch::cerr` and
+`std::terminate` will be called.
+2) If an assertion from the `REQUIRE` family of macros fails,
+`std::terminate` will be called after the active reporter returns.
+
+
+There is also a customization point for the exact behaviour of what
+happens instead of exception being thrown. To use it, define
+
+    CATCH_CONFIG_DISABLE_EXCEPTIONS_CUSTOM_HANDLER
+
+and provide a definition for this function:
+
+```cpp
+namespace Catch {
+    [[noreturn]]
+    void throw_exception(std::exception const&);
+}
+```
+
+## Overriding Catch's debug break (`-b`)
+
+> [Introduced](https://github.com/catchorg/Catch2/pull/1846) in Catch2 2.11.2.
+
+You can override Catch2's break-into-debugger code by defining the
+`CATCH_BREAK_INTO_DEBUGGER()` macro. This can be used if e.g. Catch2 does
+not know your platform, or your platform is misdetected.
+
+The macro will be used as is, that is, `CATCH_BREAK_INTO_DEBUGGER();`
+must compile and must break into debugger.
+
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/contributing.md

@@ -0,0 +1,332 @@
+<a id="top"></a>
+# Contributing to Catch2
+
+**Contents**<br>
+[Using Git(Hub)](#using-github)<br>
+[Testing your changes](#testing-your-changes)<br>
+[Writing documentation](#writing-documentation)<br>
+[Writing code](#writing-code)<br>
+[CoC](#coc)<br>
+
+So you want to contribute something to Catch2? That's great! Whether it's
+a bug fix, a new feature, support for additional compilers - or just
+a fix to the documentation - all contributions are very welcome and very
+much appreciated. Of course so are bug reports, other comments, and
+questions, but generally it is a better idea to ask questions in our
+[Discord](https://discord.gg/4CWS9zD), than in the issue tracker.
+
+
+This page covers some guidelines and helpful tips for contributing
+to the codebase itself.
+
+## Using Git(Hub)
+
+Ongoing development happens in the `devel` branch for Catch2 v3, and in
+`v2.x` for maintenance updates to the v2 versions.
+
+Commits should be small and atomic. A commit is atomic when, after it is
+applied, the codebase, tests and all, still works as expected. Small
+commits are also preferred, as they make later operations with git history,
+whether it is bisecting, reverting, or something else, easier.
+
+_When submitting a pull request please do not include changes to the
+amalgamated distribution files. This means do not include them in your
+git commits!_
+
+When addressing review comments in a MR, please do not rebase/squash the
+commits immediately. Doing so makes it harder to review the new changes,
+slowing down the process of merging a MR. Instead, when addressing review
+comments, you should append new commits to the branch and only squash
+them into other commits when the MR is ready to be merged. We recommend
+creating new commits with `git commit --fixup` (or `--squash`) and then
+later squashing them with `git rebase --autosquash` to make things easier.
+
+
+
+## Testing your changes
+
+_Note: Running Catch2's tests requires Python3_
+
+
+Catch2 has multiple layers of tests that are then run as part of our CI.
+The most obvious one are the unit tests compiled into the `SelfTest`
+binary. These are then used in "Approval tests", which run (almost) all
+tests from `SelfTest` through a specific reporter and then compare the
+generated output with a known good output ("Baseline"). By default, new
+tests should be placed here.
+
+However, not all tests can be written as plain unit tests. For example,
+checking that Catch2 orders tests randomly when asked to, and that this
+random ordering is subset-invariant, is better done as an integration
+test using an external check script. Catch2 integration tests are written
+using CTest, either as a direct command invocation + pass/fail regex,
+or by delegating the check to a Python script.
+
+Catch2 is slowly gaining more and more types of tests, currently Catch2
+project also has buildable examples, "ExtraTests", and CMake config tests.
+Examples present a small and self-contained snippets of code that
+use Catch2's facilities for specific purpose. Currently they are assumed
+passing if they compile.
+
+ExtraTests then are expensive tests, that we do not want to run all the
+time. This can be either because they take a long time to run, or because
+they take a long time to compile, e.g. because they test compile time
+configuration and require separate compilation.
+
+Finally, CMake config tests test that you set Catch2's compile-time
+configuration options through CMake, using CMake options of the same name.
+
+None of these tests are enabled by default. To enable them, add
+`-DCATCH_BUILD_EXAMPLES=ON`, `-DCATCH_BUILD_EXTRA_TESTS=ON`, and
+`-DCATCH_ENABLE_CONFIGURE_TESTS=ON` when configuration the CMake build.
+
+Bringing this all together, the steps below should configure, build,
+and run all tests in the `Debug` compilation.
+
+<!-- snippet: catch2-build-and-test -->
+<a id='snippet-catch2-build-and-test'></a>
+```sh
+# 1. Regenerate the amalgamated distribution
+./tools/scripts/generateAmalgamatedFiles.py
+
+# 2. Configure the full test build
+cmake -Bdebug-build -H. -DCMAKE_BUILD_TYPE=Debug -DCATCH_DEVELOPMENT_BUILD=ON -DCATCH_BUILD_EXAMPLES=ON -DCATCH_BUILD_EXTRA_TESTS=ON
+
+# 3. Run the actual build
+cmake --build debug-build
+
+# 4. Run the tests using CTest
+cd debug-build
+ctest -j 4 --output-on-failure -C Debug
+```
+<sup><a href='/tools/scripts/buildAndTest.sh#L6-L19' title='File snippet `catch2-build-and-test` was extracted from'>snippet source</a> | <a href='#snippet-catch2-build-and-test' title='Navigate to start of snippet `catch2-build-and-test`'>anchor</a></sup>
+<!-- endSnippet -->
+
+For convenience, the above commands are in the script `tools/scripts/buildAndTest.sh`, and can be run like this:
+
+```bash
+cd Catch2
+./tools/scripts/buildAndTest.sh
+```
+
+A Windows version of the script is available at `tools\scripts\buildAndTest.cmd`.
+
+If you added new tests, you will likely see `ApprovalTests` failure.
+After you check that the output difference is expected, you should
+run `tools/scripts/approve.py` to confirm them, and include these changes
+in your commit.
+
+
+## Writing documentation
+
+If you have added new feature to Catch2, it needs documentation, so that
+other people can use it as well. This section collects some technical
+information that you will need for updating Catch2's documentation, and
+possibly some generic advise as well.
+
+
+### Technicalities
+
+First, the technicalities:
+
+* If you have introduced a new document, there is a simple template you
+should use. It provides you with the top anchor mentioned to link to
+(more below), and also with a backlink to the top of the documentation:
+```markdown
+<a id="top"></a>
+# Cool feature
+
+> [Introduced](https://github.com/catchorg/Catch2/pull/123456) in Catch2 X.Y.Z
+
+Text that explains how to use the cool feature.
+
+
+---
+
+[Home](Readme.md#top)
+```
+
+* Crosslinks to different pages should target the `top` anchor, like this
+`[link to contributing](contributing.md#top)`.
+
+* We introduced version tags to the documentation, which show users in
+which version a specific feature was introduced. This means that newly
+written documentation should be tagged with a placeholder, that will
+be replaced with the actual version upon release. There are 2 styles
+of placeholders used through the documentation, you should pick one that
+fits your text better (if in doubt, take a look at the existing version
+tags for other features).
+  * `> [Introduced](link-to-issue-or-PR) in Catch2 X.Y.Z` - this
+  placeholder is usually used after a section heading
+  * `> X (Y and Z) was [introduced](link-to-issue-or-PR) in Catch2 X.Y.Z`
+  - this placeholder is used when you need to tag a subpart of something,
+  e.g. a list
+
+* For pages with more than 4 subheadings, we provide a table of contents
+(ToC) at the top of the page. Because GitHub markdown does not support
+automatic generation of ToC, it has to be handled semi-manually. Thus,
+if you've added a new subheading to some page, you should add it to the
+ToC. This can be done either manually, or by running the
+`updateDocumentToC.py` script in the `scripts/` folder.
+
+### Contents
+
+Now, for some content tips:
+
+* Usage examples are good. However, having large code snippets inline
+can make the documentation less readable, and so the inline snippets
+should be kept reasonably short. To provide more complex compilable
+examples, consider adding new .cpp file to `examples/`.
+
+* Don't be afraid to introduce new pages. The current documentation
+tends towards long pages, but a lot of that is caused by legacy, and
+we know that some of the pages are overly big and unfocused.
+
+* When adding information to an existing page, please try to keep your
+formatting, style and changes consistent with the rest of the page.
+
+* Any documentation has multiple different audiences, that desire
+different information from the text. The 3 basic user-types to try and
+cover are:
+  * A beginner to Catch2, who requires closer guidance for the usage of Catch2.
+  * Advanced user of Catch2, who want to customize their usage.
+  * Experts, looking for full reference of Catch2's capabilities.
+
+
+## Writing code
+
+If want to contribute code, this section contains some simple rules
+and tips on things like code formatting, code constructions to avoid,
+and so on.
+
+### C++ standard version
+
+Catch2 currently targets C++14 as the minimum supported C++ version.
+Features from higher language versions should be used only sparingly,
+when the benefits from using them outweigh the maintenance overhead.
+
+Example of good use of polyfilling features is our use of `conjunction`,
+where if available we use `std::conjunction` and otherwise provide our
+own implementation. The reason it is good is that the surface area for
+maintenance is quite small, and `std::conjunction` can directly use
+compiler built-ins, thus providing significant compilation benefits.
+
+Example of bad use of polyfilling features would be to keep around two
+sets of metaprogramming in the stringification implementation, once
+using C++14 compliant TMP and once using C++17's `if constexpr`. While
+the C++17 would provide significant compilation speedups, the maintenance
+cost would be too high.
+
+
+### Formatting
+
+To make code formatting simpler for the contributors, Catch2 provides
+its own config for `clang-format`. However, because it is currently
+impossible to replicate existing Catch2's formatting in clang-format,
+using it to reformat a whole file would cause massive diffs. To keep
+the size of your diffs reasonable, you should only use clang-format
+on the newly changed code.
+
+
+### Code constructs to watch out for
+
+This section is a (sadly incomplete) listing of various constructs that
+are problematic and are not always caught by our CI infrastructure.
+
+
+#### Naked exceptions and exceptions-related function
+
+If you are throwing an exception, it should be done via `CATCH_ERROR`
+or `CATCH_RUNTIME_ERROR` in `internal/catch_enforce.hpp`. These macros will handle
+the differences between compilation with or without exceptions for you.
+However, some platforms (IAR) also have problems with exceptions-related
+functions, such as `std::current_exceptions`. We do not have IAR in our
+CI, but luckily there should not be too many reasons to use these.
+However, if you do, they should be kept behind a
+`CATCH_CONFIG_DISABLE_EXCEPTIONS` macro.
+
+
+#### Avoid `std::move` and `std::forward`
+
+`std::move` and `std::forward` provide nice semantic name for a specific
+`static_cast`. However, being function templates they have surprisingly
+high cost during compilation, and can also have a negative performance
+impact for low-optimization builds.
+
+You should be using `CATCH_MOVE` and `CATCH_FORWARD` macros from
+`internal/catch_move_and_forward.hpp` instead. They expand into the proper
+`static_cast`, and avoid the overhead of `std::move` and `std::forward`.
+
+
+#### Unqualified usage of functions from C's stdlib
+
+If you are using a function from C's stdlib, please include the header
+as `<cfoo>` and call the function qualified. The common knowledge that
+there is no difference is wrong, QNX and VxWorks won't compile if you
+include the header as `<cfoo>` and call the function unqualified.
+
+
+#### User-Defined Literals (UDL) for Catch2' types
+
+Due to messy standardese and ... not great ... implementation of
+`-Wreserved-identifier` in Clang, avoid declaring UDLs as
+```cpp
+Approx operator "" _a(long double);
+```
+and instead declare them as
+```cpp
+Approx operator ""_a(long double);
+```
+
+Notice that the second version does not have a space between the `""` and
+the literal suffix.
+
+
+
+### New source file template
+
+If you are adding new source file, there is a template you should use.
+Specifically, every source file should start with the licence header:
+```cpp
+
+    //              Copyright Catch2 Authors
+    // Distributed under the Boost Software License, Version 1.0.
+    //   (See accompanying file LICENSE.txt or copy at
+    //        https://www.boost.org/LICENSE_1_0.txt)
+
+    // SPDX-License-Identifier: BSL-1.0
+```
+
+The include guards for header files should follow the pattern `{FILENAME}_INCLUDED`.
+This means that for file `catch_matchers_foo.hpp`, the include guard should
+be `CATCH_MATCHERS_FOO_HPP_INCLUDED`, for `catch_generators_bar.hpp`, the include
+guard should be `CATCH_GENERATORS_BAR_HPP_INCLUDED`, and so on.
+
+
+### Adding new `CATCH_CONFIG` option
+
+When adding new `CATCH_CONFIG` option, there are multiple places to edit:
+  * `CMake/CatchConfigOptions.cmake` - this is used to generate the
+    configuration options in CMake, so that CMake frontends know about them.
+  * `docs/configuration.md` - this is where the options are documented
+  * `src/catch2/catch_user_config.hpp.in` - this is template for generating
+    `catch_user_config.hpp` which contains the materialized configuration
+  * `BUILD.bazel` - Bazel does not have configuration support like CMake,
+    and all expansions need to be done manually
+  * other files as needed, e.g. `catch2/internal/catch_config_foo.hpp`
+    for the logic that guards the configuration
+
+
+## CoC
+
+This project has a [CoC](../CODE_OF_CONDUCT.md). Please adhere to it
+while contributing to Catch2.
+
+-----------
+
+_This documentation will always be in-progress as new information comes
+up, but we are trying to keep it as up to date as possible._
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/deprecations.md

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+<a id="top"></a>
+# Deprecations and incoming changes
+
+This page documents current deprecations and upcoming planned changes
+inside Catch2. The difference between these is that a deprecated feature
+will be removed, while a planned change to a feature means that the
+feature will behave differently, but will still be present. Obviously,
+either of these is a breaking change, and thus will not happen until
+at least the next major release.
+
+
+### `ParseAndAddCatchTests.cmake`
+
+The CMake/CTest integration using `ParseAndAddCatchTests.cmake` is deprecated,
+as it can be replaced by `Catch.cmake` that provides the function
+`catch_discover_tests` to get tests directly from a CMake target via the
+command line interface instead of parsing C++ code with regular expressions.
+
+
+### `CATCH_CONFIG_BAZEL_SUPPORT`
+
+Catch2 supports writing the Bazel JUnit XML output file when it is aware
+that is within a bazel testing environment. Originally there was no way
+to accurately probe the environment for this information so the flag
+`CATCH_CONFIG_BAZEL_SUPPORT` was added. This now deprecated. Bazel has now had a change
+where it will export `BAZEL_TEST=1` for purposes like the above. Catch2
+will now instead inspect the environment instead of relying on build configuration.
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/event-listeners.md

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+<a id="top"></a>
+# Event Listeners
+
+An event listener is a bit like a reporter, in that it responds to various
+reporter events in Catch2, but it is not expected to write any output.
+Instead, an event listener performs actions within the test process, such
+as performing global initialization (e.g. of a C library), or cleaning out
+in-memory logs if they are not needed (the test case passed).
+
+Unlike reporters, each registered event listener is always active. Event
+listeners are always notified before reporter(s).
+
+To write your own event listener, you should derive from `Catch::TestEventListenerBase`,
+as it provides empty stubs for all reporter events, allowing you to
+only override events you care for. Afterwards you have to register it
+with Catch2 using `CATCH_REGISTER_LISTENER` macro, so that Catch2 knows
+about it and instantiates it before running tests.
+
+Example event listener:
+```cpp
+#include <catch2/reporters/catch_reporter_event_listener.hpp>
+#include <catch2/reporters/catch_reporter_registrars.hpp>
+
+class testRunListener : public Catch::EventListenerBase {
+public:
+    using Catch::EventListenerBase::EventListenerBase;
+
+    void testRunStarting(Catch::TestRunInfo const&) override {
+        lib_foo_init();
+    }
+};
+
+CATCH_REGISTER_LISTENER(testRunListener)
+```
+
+_Note that you should not use any assertion macros within a Listener!_
+
+[You can find the list of events that the listeners can react to on its
+own page](reporter-events.md#top).
+
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/faq.md

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+<a id="top"></a>
+# Frequently Asked Questions (FAQ)
+
+**Contents**<br>
+[How do I run global setup/teardown only if tests will be run?](#how-do-i-run-global-setupteardown-only-if-tests-will-be-run)<br>
+[How do I clean up global state between running different tests?](#how-do-i-clean-up-global-state-between-running-different-tests)<br>
+[Why cannot I derive from the built-in reporters?](#why-cannot-i-derive-from-the-built-in-reporters)<br>
+[What is Catch2's ABI stability policy?](#what-is-catch2s-abi-stability-policy)<br>
+[What is Catch2's API stability policy?](#what-is-catch2s-api-stability-policy)<br>
+[Does Catch2 support running tests in parallel?](#does-catch2-support-running-tests-in-parallel)<br>
+[Can I compile Catch2 into a dynamic library?](#can-i-compile-catch2-into-a-dynamic-library)<br>
+[What repeatability guarantees does Catch2 provide?](#what-repeatability-guarantees-does-catch2-provide)<br>
+
+
+## How do I run global setup/teardown only if tests will be run?
+
+Write a custom [event listener](event-listeners.md#top) and place the
+global setup/teardown code into the `testRun*` events.
+
+
+## How do I clean up global state between running different tests?
+
+Write a custom [event listener](event-listeners.md#top) and place the
+cleanup code into either `testCase*` or `testCasePartial*` events,
+depending on how often the cleanup needs to happen.
+
+
+## Why cannot I derive from the built-in reporters?
+
+They are not made to be overridden, in that we do not attempt to maintain
+a consistent internal state if a member function is overriden, and by
+forbidding users from using them as a base class, we can refactor them
+as needed later.
+
+
+## What is Catch2's ABI stability policy?
+
+Catch2 provides no ABI stability guarantees whatsoever. Catch2 provides
+rich C++ interface, and trying to freeze its ABI would take a lot of
+pointless work.
+
+Catch2 is not designed to be distributed as dynamic library, and you
+should really be able to compile everything with the same compiler binary.
+
+
+## What is Catch2's API stability policy?
+
+Catch2 follows [semver](https://semver.org/) to the best of our ability.
+This means that we will not knowingly make backwards-incompatible changes
+without incrementing the major version number.
+
+
+## Does Catch2 support running tests in parallel?
+
+Not natively, no. We see running tests in parallel as the job of an
+external test runner, that can also run them in separate processes,
+support test execution timeouts and so on.
+
+However, Catch2 provides some tools that make the job of external test
+runners easier. [See the relevant section in our page on best
+practices](usage-tips.md#parallel-tests).
+
+
+## Can I compile Catch2 into a dynamic library?
+
+Yes, Catch2 supports the [standard CMake `BUILD_SHARED_LIBS`
+option](https://cmake.org/cmake/help/latest/variable/BUILD_SHARED_LIBS.html).
+However, the dynamic library support is provided as-is. Catch2 does not
+provide API export annotations, and so you can only use it as a dynamic
+library on platforms that default to public visibility, or with tooling
+support to force export Catch2's API.
+
+
+## What repeatability guarantees does Catch2 provide?
+
+There are two places where it is meaningful to talk about Catch2's
+repeatability guarantees without taking into account user-provided
+code. First one is in the test case shuffling, and the second one is
+the output from random generators.
+
+Test case shuffling is repeatable across different platforms since v2.12.0,
+and it is also generally repeatable across versions, but we might break
+it from time to time. E.g. we broke repeatability with previous versions
+in v2.13.4 so that test cases with similar names are shuffled better.
+
+Random generators currently rely on platform's stdlib, specifically
+the distributions from `<random>`. We thus provide no extra guarantee
+above what your platform does. **Important: `<random>`'s distributions
+are not specified to be repeatable across different platforms.**
+
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/generators.md

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+<a id="top"></a>
+# Data Generators
+
+> Introduced in Catch2 2.6.0.
+
+Data generators (also known as _data driven/parametrized test cases_)
+let you reuse the same set of assertions across different input values.
+In Catch2, this means that they respect the ordering and nesting
+of the `TEST_CASE` and `SECTION` macros, and their nested sections
+are run once per each value in a generator.
+
+This is best explained with an example:
+```cpp
+TEST_CASE("Generators") {
+    auto i = GENERATE(1, 3, 5);
+    REQUIRE(is_odd(i));
+}
+```
+
+The "Generators" `TEST_CASE` will be entered 3 times, and the value of
+`i` will be 1, 3, and 5 in turn. `GENERATE`s can also be used multiple
+times at the same scope, in which case the result will be a cartesian
+product of all elements in the generators. This means that in the snippet
+below, the test case will be run 6 (2\*3) times.
+
+```cpp
+TEST_CASE("Generators") {
+    auto i = GENERATE(1, 2);
+    auto j = GENERATE(3, 4, 5);
+}
+```
+
+There are 2 parts to generators in Catch2, the `GENERATE` macro together
+with the already provided generators, and the `IGenerator<T>` interface
+that allows users to implement their own generators.
+
+
+## Combining `GENERATE` and `SECTION`.
+
+`GENERATE` can be seen as an implicit `SECTION`, that goes from the place
+`GENERATE` is used, to the end of the scope. This can be used for various
+effects. The simplest usage is shown below, where the `SECTION` "one"
+runs 4 (2\*2) times, and `SECTION` "two" is run 6 times (2\*3).
+
+```cpp
+TEST_CASE("Generators") {
+    auto i = GENERATE(1, 2);
+    SECTION("one") {
+        auto j = GENERATE(-3, -2);
+        REQUIRE(j < i);
+    }
+    SECTION("two") {
+        auto k = GENERATE(4, 5, 6);
+        REQUIRE(i != k);
+    }
+}
+```
+
+The specific order of the `SECTION`s will be "one", "one", "two", "two",
+"two", "one"...
+
+
+The fact that `GENERATE` introduces a virtual `SECTION` can also be used
+to make a generator replay only some `SECTION`s, without having to
+explicitly add a `SECTION`. As an example, the code below reports 3
+assertions, because the "first" section is run once, but the "second"
+section is run twice.
+
+```cpp
+TEST_CASE("GENERATE between SECTIONs") {
+    SECTION("first") { REQUIRE(true); }
+    auto _ = GENERATE(1, 2);
+    SECTION("second") { REQUIRE(true); }
+}
+```
+
+This can lead to surprisingly complex test flows. As an example, the test
+below will report 14 assertions:
+
+```cpp
+TEST_CASE("Complex mix of sections and generates") {
+    auto i = GENERATE(1, 2);
+    SECTION("A") {
+        SUCCEED("A");
+    }
+    auto j = GENERATE(3, 4);
+    SECTION("B") {
+        SUCCEED("B");
+    }
+    auto k = GENERATE(5, 6);
+    SUCCEED();
+}
+```
+
+> The ability to place `GENERATE` between two `SECTION`s was [introduced](https://github.com/catchorg/Catch2/issues/1938) in Catch2 2.13.0.
+
+## Provided generators
+
+Catch2's provided generator functionality consists of three parts,
+
+* `GENERATE` macro,  that serves to integrate generator expression with
+a test case,
+* 2 fundamental generators
+  * `SingleValueGenerator<T>` -- contains only single element
+  * `FixedValuesGenerator<T>` -- contains multiple elements
+* 5 generic generators that modify other generators
+  * `FilterGenerator<T, Predicate>` -- filters out elements from a generator
+  for which the predicate returns "false"
+  * `TakeGenerator<T>` -- takes first `n` elements from a generator
+  * `RepeatGenerator<T>` -- repeats output from a generator `n` times
+  * `MapGenerator<T, U, Func>` -- returns the result of applying `Func`
+  on elements from a different generator
+  * `ChunkGenerator<T>` -- returns chunks (inside `std::vector`) of n elements from a generator
+* 4 specific purpose generators
+  * `RandomIntegerGenerator<Integral>` -- generates random Integrals from range
+  * `RandomFloatGenerator<Float>` -- generates random Floats from range
+  * `RangeGenerator<T>(first, last)` -- generates all values inside a `[first, last)` arithmetic range
+  * `IteratorGenerator<T>` -- copies and returns values from an iterator range
+
+> `ChunkGenerator<T>`, `RandomIntegerGenerator<Integral>`, `RandomFloatGenerator<Float>` and `RangeGenerator<T>` were introduced in Catch2 2.7.0.
+
+> `IteratorGenerator<T>` was introduced in Catch2 2.10.0.
+
+The generators also have associated helper functions that infer their
+type, making their usage much nicer. These are
+
+* `value(T&&)` for `SingleValueGenerator<T>`
+* `values(std::initializer_list<T>)` for `FixedValuesGenerator<T>`
+* `table<Ts...>(std::initializer_list<std::tuple<Ts...>>)` for `FixedValuesGenerator<std::tuple<Ts...>>`
+* `filter(predicate, GeneratorWrapper<T>&&)` for `FilterGenerator<T, Predicate>`
+* `take(count, GeneratorWrapper<T>&&)` for `TakeGenerator<T>`
+* `repeat(repeats, GeneratorWrapper<T>&&)` for `RepeatGenerator<T>`
+* `map(func, GeneratorWrapper<T>&&)` for `MapGenerator<T, U, Func>` (map `U` to `T`, deduced from `Func`)
+* `map<T>(func, GeneratorWrapper<U>&&)` for `MapGenerator<T, U, Func>` (map `U` to `T`)
+* `chunk(chunk-size, GeneratorWrapper<T>&&)` for `ChunkGenerator<T>`
+* `random(IntegerOrFloat a, IntegerOrFloat b)` for `RandomIntegerGenerator` or `RandomFloatGenerator`
+* `range(Arithemtic start, Arithmetic end)` for `RangeGenerator<Arithmetic>` with a step size of `1`
+* `range(Arithmetic start, Arithmetic end, Arithmetic step)` for `RangeGenerator<Arithmetic>` with a custom step size
+* `from_range(InputIterator from, InputIterator to)` for `IteratorGenerator<T>`
+* `from_range(Container const&)` for `IteratorGenerator<T>`
+
+> `chunk()`, `random()` and both `range()` functions were introduced in Catch2 2.7.0.
+
+> `from_range` has been introduced in Catch2 2.10.0
+
+> `range()` for floating point numbers has been introduced in Catch2 2.11.0
+
+And can be used as shown in the example below to create a generator
+that returns 100 odd random number:
+
+```cpp
+TEST_CASE("Generating random ints", "[example][generator]") {
+    SECTION("Deducing functions") {
+        auto i = GENERATE(take(100, filter([](int i) { return i % 2 == 1; }, random(-100, 100))));
+        REQUIRE(i > -100);
+        REQUIRE(i < 100);
+        REQUIRE(i % 2 == 1);
+    }
+}
+```
+
+
+Apart from registering generators with Catch2, the `GENERATE` macro has
+one more purpose, and that is to provide simple way of generating trivial
+generators, as seen in the first example on this page, where we used it
+as `auto i = GENERATE(1, 2, 3);`. This usage converted each of the three
+literals into a single `SingleValueGenerator<int>` and then placed them all in
+a special generator that concatenates other generators. It can also be
+used with other generators as arguments, such as `auto i = GENERATE(0, 2,
+take(100, random(300, 3000)));`. This is useful e.g. if you know that
+specific inputs are problematic and want to test them separately/first.
+
+**For safety reasons, you cannot use variables inside the `GENERATE` macro.
+This is done because the generator expression _will_ outlive the outside
+scope and thus capturing references is dangerous. If you need to use
+variables inside the generator expression, make sure you thought through
+the lifetime implications and use `GENERATE_COPY` or `GENERATE_REF`.**
+
+> `GENERATE_COPY` and `GENERATE_REF` were introduced in Catch2 2.7.1.
+
+You can also override the inferred type by using `as<type>` as the first
+argument to the macro. This can be useful when dealing with string literals,
+if you want them to come out as `std::string`:
+
+```cpp
+TEST_CASE("type conversion", "[generators]") {
+    auto str = GENERATE(as<std::string>{}, "a", "bb", "ccc");
+    REQUIRE(str.size() > 0);
+}
+```
+
+## Generator interface
+
+You can also implement your own generators, by deriving from the
+`IGenerator<T>` interface:
+
+```cpp
+template<typename T>
+struct IGenerator : GeneratorUntypedBase {
+    // via GeneratorUntypedBase:
+    // Attempts to move the generator to the next element.
+    // Returns true if successful (and thus has another element that can be read)
+    virtual bool next() = 0;
+
+    // Precondition:
+    // The generator is either freshly constructed or the last call to next() returned true
+    virtual T const& get() const = 0;
+};
+```
+
+However, to be able to use your custom generator inside `GENERATE`, it
+will need to be wrapped inside a `GeneratorWrapper<T>`.
+`GeneratorWrapper<T>` is a value wrapper around a
+`std::unique_ptr<IGenerator<T>>`.
+
+For full example of implementing your own generator, look into Catch2's
+examples, specifically
+[Generators: Create your own generator](../examples/300-Gen-OwnGenerator.cpp).
+

externals/catch/docs/limitations.md

@@ -0,0 +1,185 @@
+<a id="top"></a>
+# Known limitations
+
+Over time, some limitations of Catch2 emerged. Some of these are due
+to implementation details that cannot be easily changed, some of these
+are due to lack of development resources on our part, and some of these
+are due to plain old 3rd party bugs.
+
+
+## Implementation limits
+### Sections nested in loops
+
+If you are using `SECTION`s inside loops, you have to create them with
+different name per loop's iteration. The recommended way to do so is to
+incorporate the loop's counter into section's name, like so:
+
+```cpp
+TEST_CASE( "Looped section" ) {
+    for (char i = '0'; i < '5'; ++i) {
+        SECTION(std::string("Looped section ") + i) {
+            SUCCEED( "Everything is OK" );
+        }
+    }
+}
+```
+
+or with a `DYNAMIC_SECTION` macro (that was made for exactly this purpose):
+
+```cpp
+TEST_CASE( "Looped section" ) {
+    for (char i = '0'; i < '5'; ++i) {
+        DYNAMIC_SECTION( "Looped section " << i) {
+            SUCCEED( "Everything is OK" );
+        }
+    }
+}
+```
+
+### Tests might be run again if last section fails
+
+If the last section in a test fails, it might be run again. This is because
+Catch2 discovers `SECTION`s dynamically, as they are about to run, and
+if the last section in test case is aborted during execution (e.g. via
+the `REQUIRE` family of macros), Catch2 does not know that there are no
+more sections in that test case and must run the test case again.
+
+
+### MinGW/CygWin compilation (linking) is extremely slow
+
+Compiling Catch2 with MinGW can be exceedingly slow, especially during
+the linking step. As far as we can tell, this is caused by deficiencies
+in its default linker. If you can tell MinGW to instead use lld, via
+`-fuse-ld=lld`, the link time should drop down to reasonable length
+again.
+
+
+## Features
+This section outlines some missing features, what is their status and their possible workarounds.
+
+### Thread safe assertions
+Catch2's assertion macros are not thread safe. This does not mean that
+you cannot use threads inside Catch's test, but that only single thread
+can interact with Catch's assertions and other macros.
+
+This means that this is ok
+```cpp
+    std::vector<std::thread> threads;
+    std::atomic<int> cnt{ 0 };
+    for (int i = 0; i < 4; ++i) {
+        threads.emplace_back([&]() {
+            ++cnt; ++cnt; ++cnt; ++cnt;
+        });
+    }
+    for (auto& t : threads) { t.join(); }
+    REQUIRE(cnt == 16);
+```
+because only one thread passes the `REQUIRE` macro and this is not
+```cpp
+    std::vector<std::thread> threads;
+    std::atomic<int> cnt{ 0 };
+    for (int i = 0; i < 4; ++i) {
+        threads.emplace_back([&]() {
+            ++cnt; ++cnt; ++cnt; ++cnt;
+            CHECK(cnt == 16);
+        });
+    }
+    for (auto& t : threads) { t.join(); }
+    REQUIRE(cnt == 16);
+```
+
+Because C++11 provides the necessary tools to do this, we are planning
+to remove this limitation in the future.
+
+### Process isolation in a test
+Catch does not support running tests in isolated (forked) processes. While this might in the future, the fact that Windows does not support forking and only allows full-on process creation and the desire to keep code as similar as possible across platforms, mean that this is likely to take significant development time, that is not currently available.
+
+
+### Running multiple tests in parallel
+
+Catch2 keeps test execution in one process strictly serial, and there
+are no plans to change this. If you find yourself with a test suite
+that takes too long to run and you want to make it parallel, you have
+to run multiple processes side by side.
+
+There are 2 basic ways to do that,
+* you can split your tests into multiple binaries, and run those binaries
+  in parallel
+* you can run the same test binary multiple times, but run a different
+  subset of the tests in each process
+
+There are multiple ways to achieve the latter, the easiest way is to use
+[test sharding](command-line.md#test-sharding).
+
+
+## 3rd party bugs
+
+This section outlines known bugs in 3rd party components (this means compilers, standard libraries, standard runtimes).
+
+
+### Visual Studio 2017 -- raw string literal in assert fails to compile
+
+There is a known bug in Visual Studio 2017 (VC 15), that causes compilation
+error when preprocessor attempts to stringize a raw string literal
+(`#` preprocessor directive is applied to it). This snippet is sufficient
+to trigger the compilation error:
+
+```cpp
+#include <catch2/catch_test_macros.hpp>
+
+TEST_CASE("test") {
+    CHECK(std::string(R"("\)") == "\"\\");
+}
+```
+
+Catch2 provides a workaround, by letting the user disable stringification
+of the original expression by defining `CATCH_CONFIG_DISABLE_STRINGIFICATION`,
+like so:
+```cpp
+#define CATCH_CONFIG_DISABLE_STRINGIFICATION
+#include <catch2/catch_test_macros.hpp>
+
+TEST_CASE("test") {
+    CHECK(std::string(R"("\)") == "\"\\");
+}
+```
+
+_Do note that this changes the output:_
+```
+catchwork\test1.cpp(6):
+PASSED:
+  CHECK( Disabled by CATCH_CONFIG_DISABLE_STRINGIFICATION )
+with expansion:
+  ""\" == ""\"
+```
+
+
+### Clang/G++ -- skipping leaf sections after an exception
+Some versions of `libc++` and `libstdc++` (or their runtimes) have a bug with `std::uncaught_exception()` getting stuck returning `true` after rethrow, even if there are no active exceptions. One such case is this snippet, which skipped the sections "a" and "b", when compiled against `libcxxrt` from master
+```cpp
+#include <catch2/catch_test_macros.hpp>
+
+TEST_CASE("a") {
+    CHECK_THROWS(throw 3);
+}
+
+TEST_CASE("b") {
+    int i = 0;
+    SECTION("a") { i = 1; }
+    SECTION("b") { i = 2; }
+    CHECK(i > 0);
+}
+```
+
+If you are seeing a problem like this, i.e. weird test paths that trigger only under Clang with `libc++`, or only under very specific version of `libstdc++`, it is very likely you are seeing this. The only known workaround is to use a fixed version of your standard library.
+
+
+### libstdc++, `_GLIBCXX_DEBUG` macro and random ordering of tests
+
+Running a Catch2 binary compiled against libstdc++ with `_GLIBCXX_DEBUG`
+macro defined with `--order rand` will cause a debug check to trigger and
+abort the run due to self-assignment.
+[This is a known bug inside libstdc++](https://stackoverflow.com/questions/22915325/avoiding-self-assignment-in-stdshuffle/23691322)
+
+Workaround: Don't use `--order rand` when compiling against debug-enabled
+libstdc++.

externals/catch/docs/list-of-examples.md

@@ -0,0 +1,46 @@
+<a id="top"></a>
+# List of examples
+
+## Already available
+
+- Test Case: [Single-file](../examples/010-TestCase.cpp)
+- Test Case: [Multiple-file 1](../examples/020-TestCase-1.cpp), [2](../examples/020-TestCase-2.cpp)
+- Assertion: [REQUIRE, CHECK](../examples/030-Asn-Require-Check.cpp)
+- Fixture: [Sections](../examples/100-Fix-Section.cpp)
+- Fixture: [Class-based fixtures](../examples/110-Fix-ClassFixture.cpp)
+- BDD: [SCENARIO, GIVEN, WHEN, THEN](../examples/120-Bdd-ScenarioGivenWhenThen.cpp)
+- Listener: [Listeners](../examples/210-Evt-EventListeners.cpp)
+- Configuration: [Provide your own output streams](../examples/231-Cfg-OutputStreams.cpp)
+- Generators: [Create your own generator](../examples/300-Gen-OwnGenerator.cpp)
+- Generators: [Use map to convert types in GENERATE expression](../examples/301-Gen-MapTypeConversion.cpp)
+- Generators: [Run test with a table of input values](../examples/302-Gen-Table.cpp)
+- Generators: [Use variables in generator expressions](../examples/310-Gen-VariablesInGenerators.cpp)
+- Generators: [Use custom variable capture in generator expressions](../examples/311-Gen-CustomCapture.cpp)
+
+
+## Planned
+
+- Assertion: [REQUIRE_THAT and Matchers](../examples/040-Asn-RequireThat.cpp)
+- Assertion: [REQUIRE_NO_THROW](../examples/050-Asn-RequireNoThrow.cpp)
+- Assertion: [REQUIRE_THROWS](../examples/050-Asn-RequireThrows.cpp)
+- Assertion: [REQUIRE_THROWS_AS](../examples/070-Asn-RequireThrowsAs.cpp)
+- Assertion: [REQUIRE_THROWS_WITH](../examples/080-Asn-RequireThrowsWith.cpp)
+- Assertion: [REQUIRE_THROWS_MATCHES](../examples/090-Asn-RequireThrowsMatches.cpp)
+- Floating point: [Approx - Comparisons](../examples/130-Fpt-Approx.cpp)
+- Logging: [CAPTURE - Capture expression](../examples/140-Log-Capture.cpp)
+- Logging: [INFO - Provide information with failure](../examples/150-Log-Info.cpp)
+- Logging: [WARN - Issue warning](../examples/160-Log-Warn.cpp)
+- Logging: [FAIL, FAIL_CHECK - Issue message and force failure/continue](../examples/170-Log-Fail.cpp)
+- Logging: [SUCCEED - Issue message and continue](../examples/180-Log-Succeed.cpp)
+- Report: [User-defined type](../examples/190-Rpt-ReportUserDefinedType.cpp)
+- Report: [User-defined reporter](../examples/202-Rpt-UserDefinedReporter.cpp)
+- Report: [Automake reporter](../examples/205-Rpt-AutomakeReporter.cpp)
+- Report: [TAP reporter](../examples/206-Rpt-TapReporter.cpp)
+- Report: [Multiple reporter](../examples/208-Rpt-MultipleReporters.cpp)
+- Configuration: [Provide your own main()](../examples/220-Cfg-OwnMain.cpp)
+- Configuration: [Compile-time configuration](../examples/230-Cfg-CompileTimeConfiguration.cpp)
+- Configuration: [Run-time configuration](../examples/240-Cfg-RunTimeConfiguration.cpp)
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/logging.md

@@ -0,0 +1,159 @@
+<a id="top"></a>
+# Logging macros
+
+Additional messages can be logged during a test case. Note that the messages logged with `INFO` are scoped and thus will not be reported if failure occurs in scope preceding the message declaration. An example:
+
+```cpp
+TEST_CASE("Foo") {
+    INFO("Test case start");
+    for (int i = 0; i < 2; ++i) {
+        INFO("The number is " << i);
+        CHECK(i == 0);
+    }
+}
+
+TEST_CASE("Bar") {
+    INFO("Test case start");
+    for (int i = 0; i < 2; ++i) {
+        INFO("The number is " << i);
+        CHECK(i == i);
+    }
+    CHECK(false);
+}
+```
+When the `CHECK` fails in the "Foo" test case, then two messages will be printed.
+```
+Test case start
+The number is 1
+```
+When the last `CHECK` fails in the "Bar" test case, then only one message will be printed: `Test case start`.
+
+## Logging without local scope
+
+> [Introduced](https://github.com/catchorg/Catch2/issues/1522) in Catch2 2.7.0.
+
+`UNSCOPED_INFO` is similar to `INFO` with two key differences:
+
+- Lifetime of an unscoped message is not tied to its own scope.
+- An unscoped message can be reported by the first following assertion only, regardless of the result of that assertion.
+
+In other words, lifetime of `UNSCOPED_INFO` is limited by the following assertion (or by the end of test case/section, whichever comes first) whereas lifetime of `INFO` is limited by its own scope.
+
+These differences make this macro useful for reporting information from helper functions or inner scopes. An example:
+
+```cpp
+void print_some_info() {
+    UNSCOPED_INFO("Info from helper");
+}
+
+TEST_CASE("Baz") {
+    print_some_info();
+    for (int i = 0; i < 2; ++i) {
+        UNSCOPED_INFO("The number is " << i);
+    }
+    CHECK(false);
+}
+
+TEST_CASE("Qux") {
+    INFO("First info");
+    UNSCOPED_INFO("First unscoped info");
+    CHECK(false);
+
+    INFO("Second info");
+    UNSCOPED_INFO("Second unscoped info");
+    CHECK(false);
+}
+```
+
+"Baz" test case prints:
+```
+Info from helper
+The number is 0
+The number is 1
+```
+
+With "Qux" test case, two messages will be printed when the first `CHECK` fails:
+```
+First info
+First unscoped info
+```
+
+"First unscoped info" message will be cleared after the first `CHECK`, while "First info" message will persist until the end of the test case. Therefore, when the second `CHECK` fails, three messages will be printed:
+```
+First info
+Second info
+Second unscoped info
+```
+
+## Streaming macros
+
+All these macros allow heterogeneous sequences of values to be streaming using the insertion operator (```<<```) in the same way that std::ostream, std::cout, etc support it.
+
+E.g.:
+```c++
+INFO( "The number is " << i );
+```
+
+(Note that there is no initial ```<<``` - instead the insertion sequence is placed in parentheses.)
+These macros come in three forms:
+
+**INFO(** _message expression_ **)**
+
+The message is logged to a buffer, but only reported with next assertions that are logged. This allows you to log contextual information in case of failures which is not shown during a successful test run (for the console reporter, without -s). Messages are removed from the buffer at the end of their scope, so may be used, for example, in loops.
+
+_Note that in Catch2 2.x.x `INFO` can be used without a trailing semicolon as there is a trailing semicolon inside macro.
+This semicolon will be removed with next major version. It is highly advised to use a trailing semicolon after `INFO` macro._
+
+**UNSCOPED_INFO(** _message expression_ **)**
+
+> [Introduced](https://github.com/catchorg/Catch2/issues/1522) in Catch2 2.7.0.
+
+Similar to `INFO`, but messages are not limited to their own scope: They are removed from the buffer after each assertion, section or test case, whichever comes first.
+
+**WARN(** _message expression_ **)**
+
+The message is always reported but does not fail the test.
+
+**FAIL(** _message expression_ **)**
+
+The message is reported and the test case fails.
+
+**FAIL_CHECK(** _message expression_ **)**
+
+AS `FAIL`, but does not abort the test
+
+## Quickly capture value of variables or expressions
+
+**CAPTURE(** _expression1_, _expression2_, ... **)**
+
+Sometimes you just want to log a value of variable, or expression. For
+convenience, we provide the `CAPTURE` macro, that can take a variable,
+or an expression, and prints out that variable/expression and its value
+at the time of capture.
+
+e.g. `CAPTURE( theAnswer );` will log message "theAnswer := 42", while
+```cpp
+int a = 1, b = 2, c = 3;
+CAPTURE( a, b, c, a + b, c > b, a == 1);
+```
+will log a total of 6 messages:
+```
+a := 1
+b := 2
+c := 3
+a + b := 3
+c > b := true
+a == 1 := true
+```
+
+You can also capture expressions that use commas inside parentheses
+(e.g. function calls), brackets, or braces (e.g. initializers). To
+properly capture expression that contains template parameters list
+(in other words, it contains commas between angle brackets), you need
+to enclose the expression inside parentheses:
+`CAPTURE( (std::pair<int, int>{1, 2}) );`
+
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/matchers.md

@@ -0,0 +1,394 @@
+<a id="top"></a>
+# Matchers
+
+**Contents**<br>
+[Using Matchers](#using-matchers)<br>
+[Built-in matchers](#built-in-matchers)<br>
+[Writing custom matchers (old style)](#writing-custom-matchers-old-style)<br>
+[Writing custom matchers (new style)](#writing-custom-matchers-new-style)<br>
+
+Matchers, as popularized by the [Hamcrest](https://en.wikipedia.org/wiki/Hamcrest)
+framework are an alternative way to write assertions, useful for tests
+where you work with complex types or need to assert more complex
+properties. Matchers are easily composable and users can write their
+own and combine them with the Catch2-provided matchers seamlessly.
+
+
+## Using Matchers
+
+Matchers are most commonly used in tandem with the `REQUIRE_THAT` or
+`CHECK_THAT` macros. The `REQUIRE_THAT` macro takes two arguments,
+the first one is the input (object/value) to test, the second argument
+is the matcher itself.
+
+For example, to assert that a string ends with the "as a service"
+substring, you can write the following assertion
+
+```cpp
+using Catch::Matchers::EndsWith;
+
+REQUIRE_THAT( getSomeString(), EndsWith("as a service") );
+```
+
+Individual matchers can also be combined using the C++ logical
+operators, that is `&&`, `||`, and `!`, like so:
+
+```cpp
+using Catch::Matchers::EndsWith;
+using Catch::Matchers::ContainsSubstring;
+
+REQUIRE_THAT( getSomeString(),
+              EndsWith("as a service") && ContainsSubstring("web scale"));
+```
+
+The example above asserts that the string returned from `getSomeString`
+_both_ ends with the suffix "as a service" _and_ contains the string
+"web scale" somewhere.
+
+
+Both of the string matchers used in the examples above live in the
+`catch_matchers_string.hpp` header, so to compile the code above also
+requires `#include <catch2/matchers/catch_matchers_string.hpp>`.
+
+**IMPORTANT**: The combining operators do not take ownership of the
+matcher objects being combined. This means that if you store combined
+matcher object, you have to ensure that the matchers being combined
+outlive its last use. What this means is that the following code leads
+to a use-after-free (UAF):
+
+```cpp
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/matchers/catch_matchers_string.hpp>
+
+TEST_CASE("Bugs, bugs, bugs", "[Bug]"){
+    std::string str = "Bugs as a service";
+
+    auto match_expression = Catch::Matchers::EndsWith( "as a service" ) ||
+        (Catch::Matchers::StartsWith( "Big data" ) && !Catch::Matchers::ContainsSubstring( "web scale" ) );
+    REQUIRE_THAT(str, match_expression);
+}
+```
+
+
+## Built-in matchers
+
+Every matcher provided by Catch2 is split into 2 parts, a factory
+function that lives in the `Catch::Matchers` namespace, and the actual
+matcher type that is in some deeper namespace and should not be used by
+the user. In the examples above, we used `Catch::Matchers::Contains`.
+This is the factory function for the
+`Catch::Matchers::StdString::ContainsMatcher` type that does the actual
+matching.
+
+Out of the box, Catch2 provides the following matchers:
+
+
+### `std::string` matchers
+
+Catch2 provides 5 different matchers that work with `std::string`,
+* `StartsWith(std::string str, CaseSensitive)`,
+* `EndsWith(std::string str, CaseSensitive)`,
+* `ContainsSubstring(std::string str, CaseSensitive)`,
+* `Equals(std::string str, CaseSensitive)`, and
+* `Matches(std::string str, CaseSensitive)`.
+
+The first three should be fairly self-explanatory, they succeed if
+the argument starts with `str`, ends with `str`, or contains `str`
+somewhere inside it.
+
+The `Equals` matcher matches a string if (and only if) the argument
+string is equal to `str`.
+
+Finally, the `Matches` matcher performs an ECMAScript regex match using
+`str` against the argument string. It is important to know that
+the match is performed against the string as a whole, meaning that
+the regex `"abc"` will not match input string `"abcd"`. To match
+`"abcd"`, you need to use e.g. `"abc.*"` as your regex.
+
+The second argument sets whether the matching should be case-sensitive
+or not. By default, it is case-sensitive.
+
+> `std::string` matchers live in `catch2/matchers/catch_matchers_string.hpp`
+
+
+### Vector matchers
+
+_Vector matchers have been deprecated in favour of the generic
+range matchers with the same functionality._
+
+Catch2 provides 5 built-in matchers that work on `std::vector`.
+
+These are
+
+ * `Contains` which checks whether a specified vector is present in the result
+ * `VectorContains` which checks whether a specified element is present in the result
+ * `Equals` which checks whether the result is exactly equal (order matters) to a specific vector
+ * `UnorderedEquals` which checks whether the result is equal to a specific vector under a permutation
+ * `Approx` which checks whether the result is "approx-equal" (order matters, but comparison is done via `Approx`) to a specific vector
+> Approx matcher was [introduced](https://github.com/catchorg/Catch2/issues/1499) in Catch2 2.7.2.
+
+An example usage:
+```cpp
+    std::vector<int> some_vec{ 1, 2, 3 };
+    REQUIRE_THAT(some_vec, Catch::Matchers::UnorderedEquals(std::vector<int>{ 3, 2, 1 }));
+```
+
+This assertions will pass, because the elements given to the matchers
+are a permutation of the ones in `some_vec`.
+
+> vector matchers live in `catch2/matchers/catch_matchers_vector.hpp`
+
+
+### Floating point matchers
+
+Catch2 provides 3 matchers that target floating point numbers. These
+are:
+
+* `WithinAbs(double target, double margin)`,
+* `WithinULP(FloatingPoint target, uint64_t maxUlpDiff)`, and
+* `WithinRel(FloatingPoint target, FloatingPoint eps)`.
+
+> `WithinRel` matcher was introduced in Catch2 2.10.0
+
+For more details, read [the docs on comparing floating point
+numbers](comparing-floating-point-numbers.md#floating-point-matchers).
+
+
+### Miscellaneous matchers
+
+Catch2 also provides some matchers and matcher utilities that do not
+quite fit into other categories.
+
+The first one of them is the `Predicate(Callable pred, std::string description)`
+matcher. It creates a matcher object that calls `pred` for the provided
+argument. The `description` argument allows users to set what the
+resulting matcher should self-describe as if required.
+
+Do note that you will need to explicitly specify the type of the
+argument, like in this example:
+
+```cpp
+REQUIRE_THAT("Hello olleH",
+             Predicate<std::string>(
+                 [] (std::string const& str) -> bool { return str.front() == str.back(); },
+                 "First and last character should be equal")
+);
+```
+
+> the predicate matcher lives in `catch2/matchers/catch_matchers_predicate.hpp`
+
+
+The other miscellaneous matcher utility is exception matching.
+
+
+#### Matching exceptions
+
+Catch2 provides a utility macro for asserting that an expression
+throws exception of specific type, and that the exception has desired
+properties. The macro is `REQUIRE_THROWS_MATCHES(expr, ExceptionType, Matcher)`.
+
+> `REQUIRE_THROWS_MATCHES` macro lives in `catch2/matchers/catch_matchers.hpp`
+
+
+Catch2 currently provides only one matcher for exceptions,
+`Message(std::string message)`. `Message` checks that the exception's
+message, as returned from `what` is exactly equal to `message`.
+
+Example use:
+```cpp
+REQUIRE_THROWS_MATCHES(throwsDerivedException(),  DerivedException,  Message("DerivedException::what"));
+```
+
+Note that `DerivedException` in the example above has to derive from
+`std::exception` for the example to work.
+
+> the exception message matcher lives in `catch2/matchers/catch_matchers_exception.hpp`
+
+
+### Generic range Matchers
+
+> Generic range matchers were introduced in Catch2 3.0.1
+
+Catch2 also provides some matchers that use the new style matchers
+definitions to handle generic range-like types. These are:
+
+* `IsEmpty()`
+* `SizeIs(size_t target_size)`
+* `SizeIs(Matcher size_matcher)`
+* `Contains(T&& target_element, Comparator = std::equal_to<>{})`
+* `Contains(Matcher element_matcher)`
+* `AllMatch(Matcher element_matcher)`
+* `NoneMatch(Matcher element_matcher)`
+* `AnyMatch(Matcher element_matcher)`
+* `AllTrue()`
+* `NoneTrue()`
+* `AnyTrue()`
+
+`IsEmpty` should be self-explanatory. It successfully matches objects
+that are empty according to either `std::empty`, or ADL-found `empty`
+free function.
+
+`SizeIs` checks range's size. If constructed with `size_t` arg, the
+matchers accepts ranges whose size is exactly equal to the arg. If
+constructed from another matcher, then the resulting matcher accepts
+ranges whose size is accepted by the provided matcher.
+
+`Contains` accepts ranges that contain specific element. There are
+again two variants, one that accepts the desired element directly,
+in which case a range is accepted if any of its elements is equal to
+the target element. The other variant is constructed from a matcher,
+in which case a range is accepted if any of its elements is accepted
+by the provided matcher.
+
+`AllMatch`, `NoneMatch`, and `AnyMatch` match ranges for which either
+all, none, or any of the contained elements matches the given matcher,
+respectively.
+
+`AllTrue`, `NoneTrue`, and `AnyTrue` match ranges for which either
+all, none, or any of the contained elements are `true`, respectively.
+It works for ranges of `bool`s and ranges of elements (explicitly)
+convertible to `bool`.
+
+## Writing custom matchers (old style)
+
+The old style of writing matchers has been introduced back in Catch
+Classic. To create an old-style matcher, you have to create your own
+type that derives from `Catch::Matchers::MatcherBase<ArgT>`, where
+`ArgT` is the type your matcher works for. Your type has to override
+two methods, `bool match(ArgT const&) const`,
+and `std::string describe() const`.
+
+As the name suggests, `match` decides whether the provided argument
+is matched (accepted) by the matcher. `describe` then provides a
+human-oriented description of what the matcher does.
+
+We also recommend that you create factory function, just like Catch2
+does, but that is mostly useful for template argument deduction for
+templated matchers (assuming you do not have CTAD available).
+
+To combine these into an example, let's say that you want to write
+a matcher that decides whether the provided argument is a number
+within certain range. We will call it `IsBetweenMatcher<T>`:
+
+```c++
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/matchers/catch_matchers.hpp>
+// ...
+
+
+template <typename T>
+class IsBetweenMatcher : public Catch::Matchers::MatcherBase<T> {
+    T m_begin, m_end;
+public:
+    IsBetweenMatcher(T begin, T end) : m_begin(begin), m_end(end) {}
+
+    bool match(T const& in) const override {
+        return in >= m_begin && in <= m_end;
+    }
+
+    std::string describe() const override {
+        std::ostringstream ss;
+        ss << "is between " << m_begin << " and " << m_end;
+        return ss.str();
+    }
+};
+
+template <typename T>
+IsBetweenMatcher<T> IsBetween(T begin, T end) {
+    return { begin, end };
+}
+
+// ...
+
+TEST_CASE("Numbers are within range") {
+    // infers `double` for the argument type of the matcher
+    CHECK_THAT(3., IsBetween(1., 10.));
+    // infers `int` for the argument type of the matcher
+    CHECK_THAT(100, IsBetween(1, 10));
+}
+```
+
+Obviously, the code above can be improved somewhat, for example you
+might want to `static_assert` over the fact that `T` is an arithmetic
+type... or generalize the matcher to cover any type for which the user
+can provide a comparison function object.
+
+Note that while any matcher written using the old style can also be
+written using the new style, combining old style matchers should
+generally compile faster. Also note that you can combine old and new
+style matchers arbitrarily.
+
+> `MatcherBase` lives in `catch2/matchers/catch_matchers.hpp`
+
+
+## Writing custom matchers (new style)
+
+> New style matchers were introduced in Catch2 3.0.1
+
+To create a new-style matcher, you have to create your own type that
+derives from `Catch::Matchers::MatcherGenericBase`. Your type has to
+also provide two methods, `bool match( ... ) const` and overridden
+`std::string describe() const`.
+
+Unlike with old-style matchers, there are no requirements on how
+the `match` member function takes its argument. This means that the
+argument can be taken by value or by mutating reference, but also that
+the matcher's `match` member function can be templated.
+
+This allows you to write more complex matcher, such as a matcher that
+can compare one range-like (something that responds to `begin` and
+`end`) object to another, like in the following example:
+
+```cpp
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/matchers/catch_matchers_templated.hpp>
+// ...
+
+template<typename Range>
+struct EqualsRangeMatcher : Catch::Matchers::MatcherGenericBase {
+    EqualsRangeMatcher(Range const& range):
+        range{ range }
+    {}
+
+    template<typename OtherRange>
+    bool match(OtherRange const& other) const {
+        using std::begin; using std::end;
+
+        return std::equal(begin(range), end(range), begin(other), end(other));
+    }
+
+    std::string describe() const override {
+        return "Equals: " + Catch::rangeToString(range);
+    }
+
+private:
+    Range const& range;
+};
+
+template<typename Range>
+auto EqualsRange(const Range& range) -> EqualsRangeMatcher<Range> {
+    return EqualsRangeMatcher<Range>{range};
+}
+
+TEST_CASE("Combining templated matchers", "[matchers][templated]") {
+    std::array<int, 3> container{{ 1,2,3 }};
+
+    std::array<int, 3> a{{ 1,2,3 }};
+    std::vector<int> b{ 0,1,2 };
+    std::list<int> c{ 4,5,6 };
+
+    REQUIRE_THAT(container, EqualsRange(a) || EqualsRange(b) || EqualsRange(c));
+}
+```
+
+Do note that while you can rewrite any matcher from the old style to
+a new style matcher, combining new style matchers is more expensive
+in terms of compilation time. Also note that you can combine old style
+and new style matchers arbitrarily.
+
+> `MatcherGenericBase` lives in `catch2/matchers/catch_matchers_templated.hpp`
+
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/migrate-v2-to-v3.md

@@ -0,0 +1,98 @@
+<a id="top"></a>
+# Migrating from v2 to v3
+
+v3 is the next major version of Catch2 and brings three significant changes:
+ * Catch2 is now split into multiple headers
+ * Catch2 is now compiled as a static library
+ * C++14 is the minimum required C++ version
+
+There are many reasons why we decided to go from the old single-header
+distribution model to a more standard library distribution model. The
+big one is compile-time performance, but moving over to a split header
+distribution model also improves the future maintainability and
+extendability of the codebase. For example v3 adds a new kind of matchers
+without impacting the compilation times of users that do not use matchers
+in their tests. The new model is also more friendly towards package
+managers, such as vcpkg and Conan.
+
+The result of this move is a significant improvement in compilation
+times, e.g. the inclusion overhead of Catch2 in the common case has been
+reduced by roughly 80%. The improved ease of maintenance also led to
+various runtime performance improvements and the introduction of new features.
+For details, look at [the release notes of 3.0.1](release-notes.md#301).
+
+_Note that we still provide one header + one translation unit (TU)
+distribution but do not consider it the primarily supported option. You
+should also expect that the compilation times will be worse if you use
+this option._
+
+
+## How to migrate projects from v2 to v3
+
+To migrate to v3, there are two basic approaches to do so.
+
+1. Use `catch_amalgamated.hpp` and `catch_amalgamated.cpp`.
+2. Build Catch2 as a proper (static) library, and move to piecewise headers
+
+Doing 1 means downloading the [amalgamated header](/extras/catch_amalgamated.hpp)
+and the [amalgamated sources](/extras/catch_amalgamated.cpp) from `extras`,
+dropping them into your test project, and rewriting your includes from
+`<catch2/catch.hpp>` to `"catch_amalgamated.hpp"` (or something similar,
+based on how you set up your paths).
+
+The disadvantage of using this approach are increased compilation times,
+at least compared to the second approach, but it does let you avoid
+dealing with consuming libraries in your build system of choice.
+
+
+However, we recommend doing 2, and taking extra time to migrate to v3
+properly. This lets you reap the benefits of significantly improved
+compilation times in the v3 version. The basic steps to do so are:
+
+1. Change your CMakeLists.txt to link against `Catch2WithMain` target if
+you use Catch2's default main. (If you do not, keep linking against
+the `Catch2` target.). If you use pkg-config, change `pkg-config catch2` to
+`pkg-config catch2-with-main`.
+2. Delete TU with `CATCH_CONFIG_RUNNER` or `CATCH_CONFIG_MAIN` defined,
+as it is no longer needed.
+3. Change `#include <catch2/catch.hpp>` to `#include <catch2/catch_all.hpp>`
+4. Check that everything compiles. You might have to modify namespaces,
+or perform some other changes (see the
+[Things that can break during porting](#things-that-can-break-during-porting)
+section for the most common things).
+5. Start migrating your test TUs from including `<catch2/catch_all.hpp>`
+to piecemeal includes. You will likely want to start by including
+`<catch2/catch_test_macros.hpp>`, and then go from there. (see
+[other notes](#other-notes) for further ideas)
+
+## Other notes
+
+* The main test include is now `<catch2/catch_test_macros.hpp>`
+
+* Big "subparts" like Matchers, or Generators, have their own folder, and
+also their own "big header", so if you just want to include all matchers,
+you can include `<catch2/matchers/catch_matchers_all.hpp>`,
+or `<catch2/generators/catch_generators_all.hpp>`
+
+
+## Things that can break during porting
+
+* The namespaces of Matchers were flattened and cleaned up.
+
+Matchers are no longer declared deep within an internal namespace and
+then brought up into `Catch` namespace. All Matchers now live in the
+`Catch::Matchers` namespace.
+
+* The `Contains` string matcher was renamed to `ContainsSubstring`.
+
+* The reporter interfaces changed in a breaking manner.
+
+If you are using a custom reporter or listener, you will likely need to
+modify them to conform to the new interfaces. Unlike before in v2,
+the [interfaces](reporters.md#top) and the [events](reporter-events.md#top)
+are now documented.
+
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/opensource-users.md

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+<a id="top"></a>
+# Open Source projects using Catch2
+
+Catch2 is great for open source. It is licensed under the [Boost Software
+License (BSL)](../LICENSE.txt), has no further dependencies and supports
+two file distribution.
+
+As a result, Catch2 is used for testing in many different Open Source
+projects. This page lists at least some of them, even though it will
+obviously never be complete (and does not have the ambition to be
+complete). Note that the list below is intended to be in alphabetical
+order, to avoid implications of relative importance of the projects.
+
+_Please only add projects here if you are their maintainer, or have the
+maintainer's explicit consent._
+
+
+## Libraries & Frameworks
+
+### [accessorpp](https://github.com/wqking/accessorpp)
+C++ library for implementing property and data binding.
+
+### [alpaka](https://github.com/alpaka-group/alpaka)
+A header-only C++14 abstraction library for accelerator development.
+
+### [ApprovalTests.cpp](https://github.com/approvals/ApprovalTests.cpp)
+C++11 implementation of Approval Tests, for quick, convenient testing of legacy code.
+
+### [args](https://github.com/Taywee/args)
+A simple header-only C++ argument parser library.
+
+### [Azmq](https://github.com/zeromq/azmq)
+Boost Asio style bindings for ZeroMQ.
+
+### [Cataclysm: Dark Days Ahead](https://github.com/CleverRaven/Cataclysm-DDA)
+Post-apocalyptic survival RPG.
+
+### [ChaiScript](https://github.com/ChaiScript/ChaiScript)
+A, header-only, embedded scripting language designed from the ground up to directly target C++ and take advantage of modern C++ development techniques.
+
+### [ChakraCore](https://github.com/Microsoft/ChakraCore)
+The core part of the Chakra JavaScript engine that powers Microsoft Edge.
+
+### [Clara](https://github.com/philsquared/Clara)
+A, single-header-only, type-safe, command line parser - which also prints formatted usage strings.
+
+### [Couchbase-lite-core](https://github.com/couchbase/couchbase-lite-core)
+The next-generation core storage and query engine for Couchbase Lite.
+
+### [cppcodec](https://github.com/tplgy/cppcodec)
+Header-only C++11 library to encode/decode base64, base64url, base32, base32hex and hex (a.k.a. base16) as specified in RFC 4648, plus Crockford's base32.
+
+### [DtCraft](https://github.com/twhuang-uiuc/DtCraft)
+A High-performance Cluster Computing Engine.
+
+### [eventpp](https://github.com/wqking/eventpp)
+C++ event library for callbacks, event dispatcher, and event queue. With eventpp you can easily implement signal and slot mechanism, publisher and subscriber pattern, or observer pattern.
+
+### [forest](https://github.com/xorz57/forest)
+Template Library of Tree Data Structures.
+
+### [Fuxedo](https://github.com/fuxedo/fuxedo)
+Open source Oracle Tuxedo-like XATMI middleware for C and C++.
+
+### [HIP CPU Runtime](https://github.com/ROCm-Developer-Tools/HIP-CPU)
+A header-only library that allows CPUs to execute unmodified HIP code. It is generic and does not assume a particular CPU vendor or architecture.
+
+### [Inja](https://github.com/pantor/inja)
+A header-only template engine for modern C++.
+
+### [LLAMA](https://github.com/alpaka-group/llama)
+A C++17 template header-only library for the abstraction of memory access patterns.
+
+### [libcluon](https://github.com/chrberger/libcluon)
+A single-header-only library written in C++14 to glue distributed software components (UDP, TCP, shared memory) supporting natively Protobuf, LCM/ZCM, MsgPack, and JSON for dynamic message transformations in-between.
+
+### [MNMLSTC Core](https://github.com/mnmlstc/core)
+A small and easy to use C++11 library that adds a functionality set that will be available in C++14 and later, as well as some useful additions.
+
+### [nanodbc](https://github.com/lexicalunit/nanodbc/)
+A small C++ library wrapper for the native C ODBC API.
+
+### [Nonius](https://github.com/libnonius/nonius)
+A header-only framework for benchmarking small snippets of C++ code.
+
+### [OpenALpp](https://github.com/Laguna1989/OpenALpp)
+A modern OOP C++14 audio library built on OpenAL for Windows, Linux and web (emscripten).
+
+### [polymorphic_value](https://github.com/jbcoe/polymorphic_value)
+A polymorphic value-type for C++.
+
+### [Ppconsul](https://github.com/oliora/ppconsul)
+A C++ client library for Consul. Consul is a distributed tool for discovering and configuring services in your infrastructure.
+
+### [Reactive-Extensions/ RxCpp](https://github.com/Reactive-Extensions/RxCpp)
+A library of algorithms for values-distributed-in-time.
+
+### [SOCI](https://github.com/SOCI/soci)
+The C++ Database Access Library.
+
+### [TextFlowCpp](https://github.com/philsquared/textflowcpp)
+A small, single-header-only, library for wrapping and composing columns of text.
+
+### [thor](https://github.com/xorz57/thor)
+Wrapper Library for CUDA.
+
+### [toml++](https://github.com/marzer/tomlplusplus)
+A header-only TOML parser and serializer for modern C++.
+
+### [Trompeloeil](https://github.com/rollbear/trompeloeil)
+A thread-safe header-only mocking framework for C++14.
+
+## Applications & Tools
+
+### [App Mesh](https://github.com/laoshanxi/app-mesh)
+A high available cloud native micro-service application management platform implemented by modern C++.
+
+### [ArangoDB](https://github.com/arangodb/arangodb)
+ArangoDB is a native multi-model database with flexible data models for documents, graphs, and key-values.
+
+### [Cytopia](https://github.com/CytopiaTeam/Cytopia)
+Cytopia is a free, open source retro pixel-art city building game with a big focus on mods. It utilizes a custom isometric rendering engine based on SDL2.
+
+### [d-SEAMS](https://github.com/d-SEAMS/seams-core)
+Open source molecular dynamics simulation structure analysis suite of tools in modern C++.
+
+### [Giada - Your Hardcore Loop Machine](https://github.com/monocasual/giada)
+Minimal, open-source and cross-platform audio tool for live music production.
+
+### [MAME](https://github.com/mamedev/mame)
+MAME originally stood for Multiple Arcade Machine Emulator.
+
+### [Newsbeuter](https://github.com/akrennmair/newsbeuter)
+Newsbeuter is an open-source RSS/Atom feed reader for text terminals.
+
+### [PopHead](https://github.com/SPC-Some-Polish-Coders/PopHead)
+A 2D, Zombie, RPG game which is being made on our own engine.
+
+### [raspigcd](https://github.com/pantadeusz/raspigcd)
+Low level CLI app and library for execution of GCODE on Raspberry Pi without any additional microcontrolers (just RPi + Stepsticks).
+
+### [SpECTRE](https://github.com/sxs-collaboration/spectre)
+SpECTRE is a code for multi-scale, multi-physics problems in astrophysics and gravitational physics.
+
+### [Standardese](https://github.com/foonathan/standardese)
+Standardese aims to be a nextgen Doxygen.
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/other-macros.md

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+<a id="top"></a>
+# Other macros
+
+This page serves as a reference for macros that are not documented
+elsewhere. For now, these macros are separated into 2 rough categories,
+"assertion related macros" and "test case related macros".
+
+## Assertion related macros
+
+* `CHECKED_IF` and `CHECKED_ELSE`
+
+`CHECKED_IF( expr )` is an `if` replacement, that also applies Catch2's
+stringification machinery to the _expr_ and records the result. As with
+`if`, the block after a `CHECKED_IF` is entered only if the expression
+evaluates to `true`. `CHECKED_ELSE( expr )` work similarly, but the block
+is entered only if the _expr_ evaluated to `false`.
+
+> `CHECKED_X` macros were changed to not count as failure in Catch2 3.0.1.
+
+Example:
+```cpp
+int a = ...;
+int b = ...;
+CHECKED_IF( a == b ) {
+    // This block is entered when a == b
+} CHECKED_ELSE ( a == b ) {
+    // This block is entered when a != b
+}
+```
+
+* `CHECK_NOFAIL`
+
+`CHECK_NOFAIL( expr )` is a variant of `CHECK` that does not fail the test
+case if _expr_ evaluates to `false`. This can be useful for checking some
+assumption, that might be violated without the test necessarily failing.
+
+Example output:
+```
+main.cpp:6:
+FAILED - but was ok:
+  CHECK_NOFAIL( 1 == 2 )
+
+main.cpp:7:
+PASSED:
+  CHECK( 2 == 2 )
+```
+
+* `SUCCEED`
+
+`SUCCEED( msg )` is mostly equivalent with `INFO( msg ); REQUIRE( true );`.
+In other words, `SUCCEED` is for cases where just reaching a certain line
+means that the test has been a success.
+
+Example usage:
+```cpp
+TEST_CASE( "SUCCEED showcase" ) {
+    int I = 1;
+    SUCCEED( "I is " << I );
+}
+```
+
+* `STATIC_REQUIRE` and `STATIC_CHECK`
+
+> `STATIC_REQUIRE` was [introduced](https://github.com/catchorg/Catch2/issues/1362) in Catch2 2.4.2.
+
+`STATIC_REQUIRE( expr )` is a macro that can be used the same way as a
+`static_assert`, but also registers the success with Catch2, so it is
+reported as a success at runtime. The whole check can also be deferred
+to the runtime, by defining `CATCH_CONFIG_RUNTIME_STATIC_REQUIRE` before
+including the Catch2 header.
+
+Example:
+```cpp
+TEST_CASE("STATIC_REQUIRE showcase", "[traits]") {
+    STATIC_REQUIRE( std::is_void<void>::value );
+    STATIC_REQUIRE_FALSE( std::is_void<int>::value );
+}
+```
+
+> `STATIC_CHECK` was [introduced](https://github.com/catchorg/Catch2/pull/2318) in Catch2 3.0.1.
+
+`STATIC_CHECK( expr )` is equivalent to `STATIC_REQUIRE( expr )`, with the
+difference that when `CATCH_CONFIG_RUNTIME_STATIC_REQUIRE` is defined, it
+becomes equivalent to `CHECK` instead of `REQUIRE`.
+
+Example:
+```cpp
+TEST_CASE("STATIC_CHECK showcase", "[traits]") {
+    STATIC_CHECK( std::is_void<void>::value );
+    STATIC_CHECK_FALSE( std::is_void<int>::value );
+}
+```
+
+## Test case related macros
+
+* `METHOD_AS_TEST_CASE`
+
+`METHOD_AS_TEST_CASE( member-function-pointer, description )` lets you
+register a member function of a class as a Catch2 test case. The class
+will be separately instantiated for each method registered in this way.
+
+```cpp
+class TestClass {
+    std::string s;
+
+public:
+    TestClass()
+        :s( "hello" )
+    {}
+
+    void testCase() {
+        REQUIRE( s == "hello" );
+    }
+};
+
+
+METHOD_AS_TEST_CASE( TestClass::testCase, "Use class's method as a test case", "[class]" )
+```
+
+* `REGISTER_TEST_CASE`
+
+`REGISTER_TEST_CASE( function, description )` let's you register
+a `function` as a test case. The function has to have `void()` signature,
+the description can contain both name and tags.
+
+Example:
+```cpp
+REGISTER_TEST_CASE( someFunction, "ManuallyRegistered", "[tags]" );
+```
+
+_Note that the registration still has to happen before Catch2's session
+is initiated. This means that it either needs to be done in a global
+constructor, or before Catch2's session is created in user's own main._
+
+
+* `DYNAMIC_SECTION`
+
+> Introduced in Catch2 2.3.0.
+
+`DYNAMIC_SECTION` is a `SECTION` where the user can use `operator<<` to
+create the final name for that section. This can be useful with e.g.
+generators, or when creating a `SECTION` dynamically, within a loop.
+
+Example:
+```cpp
+TEST_CASE( "looped SECTION tests" ) {
+    int a = 1;
+
+    for( int b = 0; b < 10; ++b ) {
+        DYNAMIC_SECTION( "b is currently: " << b ) {
+            CHECK( b > a );
+        }
+    }
+}
+```

externals/catch/docs/own-main.md

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+<a id="top"></a>
+# Supplying main() yourself
+
+**Contents**<br>
+[Let Catch2 take full control of args and config](#let-catch2-take-full-control-of-args-and-config)<br>
+[Amending the Catch2 config](#amending-the-catch2-config)<br>
+[Adding your own command line options](#adding-your-own-command-line-options)<br>
+[Version detection](#version-detection)<br>
+
+The easiest way to use Catch2 is to use its own `main` function, and let
+it handle the command line arguments. This is done by linking against
+Catch2Main library, e.g. through the [CMake target](cmake-integration.md#cmake-targets),
+or pkg-config files.
+
+If you want to provide your own `main`, then you should link against
+the static library (target) only, without the main part. You will then
+have to write your own `main` and call into Catch2 test runner manually.
+
+Below are some basic recipes on what you can do supplying your own main.
+
+
+## Let Catch2 take full control of args and config
+
+This is useful if you just need to have code that executes before/after
+Catch2 runs tests.
+
+```cpp
+#include <catch2/catch_session.hpp>
+
+int main( int argc, char* argv[] ) {
+  // your setup ...
+
+  int result = Catch::Session().run( argc, argv );
+
+  // your clean-up...
+
+  return result;
+}
+```
+
+_Note that if you only want to run some set up before tests are run, it
+might be simpler to use [event listeners](event-listeners.md#top) instead._
+
+
+## Amending the Catch2 config
+
+If you want Catch2 to process command line arguments, but also want to
+programmatically change the resulting configuration of Catch2 run,
+you can do it in two ways:
+
+```c++
+int main( int argc, char* argv[] ) {
+  Catch::Session session; // There must be exactly one instance
+
+  // writing to session.configData() here sets defaults
+  // this is the preferred way to set them
+
+  int returnCode = session.applyCommandLine( argc, argv );
+  if( returnCode != 0 ) // Indicates a command line error
+        return returnCode;
+
+  // writing to session.configData() or session.Config() here
+  // overrides command line args
+  // only do this if you know you need to
+
+  int numFailed = session.run();
+
+  // numFailed is clamped to 255 as some unices only use the lower 8 bits.
+  // This clamping has already been applied, so just return it here
+  // You can also do any post run clean-up here
+  return numFailed;
+}
+```
+
+If you want full control of the configuration, don't call `applyCommandLine`.
+
+
+## Adding your own command line options
+
+You can add new command line options to Catch2, by composing the premade
+CLI parser (called Clara), and add your own options.
+
+```cpp
+int main( int argc, char* argv[] ) {
+  Catch::Session session; // There must be exactly one instance
+
+  int height = 0; // Some user variable you want to be able to set
+
+  // Build a new parser on top of Catch2's
+  using namespace Catch::Clara;
+  auto cli
+    = session.cli()           // Get Catch2's command line parser
+    | Opt( height, "height" ) // bind variable to a new option, with a hint string
+        ["-g"]["--height"]    // the option names it will respond to
+        ("how high?");        // description string for the help output
+
+  // Now pass the new composite back to Catch2 so it uses that
+  session.cli( cli );
+
+  // Let Catch2 (using Clara) parse the command line
+  int returnCode = session.applyCommandLine( argc, argv );
+  if( returnCode != 0 ) // Indicates a command line error
+      return returnCode;
+
+  // if set on the command line then 'height' is now set at this point
+  if( height > 0 )
+      std::cout << "height: " << height << std::endl;
+
+  return session.run();
+}
+```
+
+See the [Clara documentation](https://github.com/catchorg/Clara/blob/master/README.md)
+for more details on how to use the Clara parser.
+
+
+## Version detection
+
+Catch2 provides a triplet of macros providing the header's version,
+
+* `CATCH_VERSION_MAJOR`
+* `CATCH_VERSION_MINOR`
+* `CATCH_VERSION_PATCH`
+
+these macros expand into a single number, that corresponds to the appropriate
+part of the version. As an example, given single header version v2.3.4,
+the macros would expand into `2`, `3`, and `4` respectively.
+
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/release-process.md

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+<a id="top"></a>
+# How to release
+
+When enough changes have accumulated, it is time to release new version of Catch. This document describes the process in doing so, that no steps are forgotten. Note that all referenced scripts can be found in the `tools/scripts/` directory.
+
+## Necessary steps
+
+These steps are necessary and have to be performed before each new release. They serve to make sure that the new release is correct and linked-to from the standard places.
+
+
+### Testing
+
+All of the tests are currently run in our CI setup based on TravisCI and
+AppVeyor. As long as the last commit tested green, the release can
+proceed.
+
+
+### Incrementing version number
+
+Catch uses a variant of [semantic versioning](http://semver.org/), with breaking API changes (and thus major version increments) being very rare. Thus, the release will usually increment the patch version, when it only contains couple of bugfixes, or minor version, when it contains new functionality, or larger changes in implementation of current functionality.
+
+After deciding which part of version number should be incremented, you can use one of the `*Release.py` scripts to perform the required changes to Catch.
+
+This will take care of generating the single include header, updating
+version numbers everywhere and pushing the new version to Wandbox.
+
+
+### Release notes
+
+Once a release is ready, release notes need to be written. They should summarize changes done since last release. For rough idea of expected notes see previous releases. Once written, release notes should be added to `docs/release-notes.md`.
+
+
+### Commit and push update to GitHub
+
+After version number is incremented, single-include header is regenerated and release notes are updated, changes should be committed and pushed to GitHub.
+
+
+### Release on GitHub
+
+After pushing changes to GitHub, GitHub release *needs* to be created.
+Tag version and release title should be same as the new version,
+description should contain the release notes for the current release.
+We also attach the two amalgamated files as "binaries".
+
+Since 2.5.0, the release tag and the "binaries" (amalgamated files) should
+be PGP signed.
+
+#### Signing a tag
+
+To create a signed tag, use `git tag -s <VERSION>`, where `<VERSION>`
+is the version being released, e.g. `git tag -s v2.6.0`.
+
+Use the version name as the short message and the release notes as
+the body (long) message.
+
+#### Signing the amalgamated files
+
+This will create ASCII-armored signatures for the two amalgamated files
+that are uploaded to the GitHub release:
+
+```
+gpg --armor --output extras/catch_amalgamated.hpp.asc --detach-sig extras/catch_amalgamated.hpp
+gpg --armor --output extras/catch_amalgamated.cpp.asc --detach-sig extras/catch_amalgamated.cpp
+```
+
+_GPG does not support signing multiple files in single invocation._

externals/catch/docs/reporter-events.md

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+<a id="top"></a>
+# Reporter events
+
+**Contents**<br>
+[Test running events](#test-running-events)<br>
+[Benchmarking events](#benchmarking-events)<br>
+[Listings events](#listings-events)<br>
+[Miscellaneous events](#miscellaneous-events)<br>
+
+Reporter events are one of the customization points for user code. They
+are used by [reporters](reporters.md#top) to customize Catch2's output,
+and by [event listeners](event-listeners.md#top) to perform in-process
+actions under some conditions.
+
+There are currently 21 reporter events in Catch2, split between 4 distinct
+event groups:
+* test running events (10 events)
+* benchmarking (4 events)
+* listings (3 events)
+* miscellaneous (4 events)
+
+## Test running events
+
+Test running events are always paired so that for each `fooStarting` event,
+there is a `fooEnded` event. This means that the 10 test running events
+consist of 5 pairs of events:
+
+* `testRunStarting` and `testRunEnded`,
+* `testCaseStarting` and `testCaseEnded`,
+* `testCasePartialStarting` and `testCasePartialEnded`,
+* `sectionStarting` and `sectionEnded`,
+* `assertionStarting` and `assertionEnded`
+
+### `testRun` events
+
+```cpp
+void testRunStarting( TestRunInfo const& testRunInfo );
+void testRunEnded( TestRunStats const& testRunStats );
+```
+
+The `testRun` events bookend the entire test run. `testRunStarting` is
+emitted before the first test case is executed, and `testRunEnded` is
+emitted after all the test cases have been executed.
+
+### `testCase` events
+
+```cpp
+void testCaseStarting( TestCaseInfo const& testInfo );
+void testCaseEnded( TestCaseStats const& testCaseStats );
+```
+
+The `testCase` events bookend one _full_ run of a specific test case.
+Individual runs through a test case, e.g. due to `SECTION`s or `GENERATE`s,
+are handled by a different event.
+
+
+### `testCasePartial` events
+
+> Introduced in Catch2 3.0.1
+
+```cpp
+void testCasePartialStarting( TestCaseInfo const& testInfo, uint64_t partNumber );
+void testCasePartialEnded(TestCaseStats const& testCaseStats, uint64_t partNumber );
+```
+
+`testCasePartial` events bookend one _partial_ run of a specific test case.
+This means that for any given test case, these events can be emitted
+multiple times, e.g. due to multiple leaf sections.
+
+In regards to nesting with `testCase` events, `testCasePartialStarting`
+will never be emitted before the corresponding `testCaseStarting`, and
+`testCasePartialEnded` will always be emitted before the corresponding
+`testCaseEnded`.
+
+
+### `section` events
+
+```cpp
+void sectionStarting( SectionInfo const& sectionInfo );
+void sectionEnded( SectionStats const& sectionStats );
+```
+
+`section` events are emitted only for active `SECTION`s, that is, sections
+that are entered. Sections that are skipped in this test case run-through
+do not cause events to be emitted.
+
+_Note that test cases always contain one implicit section. The event for
+this section is emitted after the corresponding `testCasePartialStarting`
+event._
+
+
+### `assertion` events
+
+```cpp
+void assertionStarting( AssertionInfo const& assertionInfo );
+void assertionEnded( AssertionStats const& assertionStats );
+```
+
+`assertionStarting` is called after the expression is captured, but before
+the assertion expression is evaluated. This might seem like a minor
+distinction, but what it means is that if you have assertion like
+`REQUIRE( a + b == c + d )`, then what happens is that `a + b` and `c + d`
+are evaluated before `assertionStarting` is emitted, while the `==` is
+evaluated after the event.
+
+
+## Benchmarking events
+
+> [Introduced](https://github.com/catchorg/Catch2/issues/1616) in Catch2 2.9.0.
+
+```cpp
+void benchmarkPreparing( StringRef name ) override;
+void benchmarkStarting( BenchmarkInfo const& benchmarkInfo ) override;
+void benchmarkEnded( BenchmarkStats<> const& benchmarkStats ) override;
+void benchmarkFailed( StringRef error ) override;
+```
+
+Due to the benchmark lifecycle being bit more complicated, the benchmarking
+events have their own category, even though they could be seen as parallel
+to the `assertion*` events. You should expect running a benchmark to
+generate at least 2 of the events above.
+
+To understand the explanation below, you should read the [benchmarking
+documentation](benchmarks.md#top) first.
+
+* `benchmarkPreparing` event is sent after the environmental probe
+finishes, but before the user code is first estimated.
+* `benchmarkStarting` event is sent after the user code is estimated,
+but has not been benchmarked yet.
+* `benchmarkEnded` event is sent after the user code has been benchmarked,
+and contains the benchmarking results.
+* `benchmarkFailed` event is sent if either the estimation or the
+benchmarking itself fails.
+
+
+## Listings events
+
+> Introduced in Catch2 3.0.1.
+
+Listings events are events that correspond to the test binary being
+invoked with `--list-foo` flag.
+
+There are currently 3 listing events, one for reporters, one for tests,
+and one for tags. Note that they are not exclusive to each other.
+
+```cpp
+void listReporters( std::vector<ReporterDescription> const& descriptions );
+void listTests( std::vector<TestCaseHandle> const& tests );
+void listTags( std::vector<TagInfo> const& tagInfos );
+```
+
+
+## Miscellaneous events
+
+```cpp
+void reportInvalidTestSpec( StringRef unmatchedSpec );
+void fatalErrorEncountered( StringRef error );
+void noMatchingTestCases( StringRef unmatchedSpec );
+```
+
+These are one-off events that do not neatly fit into other categories.
+
+`reportInvalidTestSpec` is sent for each [test specification command line
+argument](command-line.md#specifying-which-tests-to-run) that wasn't
+parsed into a valid spec.
+
+`fatalErrorEncountered` is sent when Catch2's POSIX signal handling
+or Windows SE handler is called into with a fatal signal/exception.
+
+`noMatchingTestCases` is sent for each user provided test specification
+that did not match any registered tests.
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/reporters.md

@@ -0,0 +1,213 @@
+<a id="top"></a>
+# Reporters
+
+Reporters are a customization point for most of Catch2's output, e.g.
+formatting and writing out [assertions (whether passing or failing),
+sections, test cases, benchmarks, and so on](reporter-events.md#top).
+
+Catch2 comes with a bunch of reporters by default (currently 8), and
+you can also write your own reporter. Because multiple reporters can
+be active at the same time, your own reporters do not even have to handle
+all reporter event, just the ones you are interested in, e.g. benchmarks.
+
+
+## Using different reporters
+
+You can see which reporters are available by running the test binary
+with `--list-reporters`. You can then pick one of them with the [`-r`,
+`--reporter` option](command-line.md#choosing-a-reporter-to-use), followed
+by the name of the desired reporter, like so:
+
+```
+--reporter xml
+```
+
+You can also select multiple reporters to be used at the same time.
+In that case you should read the [section on using multiple
+reporters](#multiple-reporters) to avoid any surprises from doing so.
+
+
+<a id="multiple-reporters"></a>
+## Using multiple reporters
+
+> Support for having multiple parallel reporters was [introduced](https://github.com/catchorg/Catch2/pull/2183) in Catch2 3.0.1
+
+Catch2 supports using multiple reporters at the same time while having
+them write into different destinations. The two main uses of this are
+
+* having both human-friendly and machine-parseable (e.g. in JUnit format)
+  output from one run of binary
+* having "partial" reporters that are highly specialized, e.g. having one
+  reporter that writes out benchmark results as markdown tables and does
+  nothing else, while also having standard testing output separately
+
+Specifying multiple reporter looks like this:
+```
+--reporter JUnit::out=result-junit.xml --reporter console::out=-::colour-mode=ansi
+```
+
+This tells Catch2 to use two reporters, `JUnit` reporter that writes
+its machine-readable XML output to file `result-junit.xml`, and the
+`console` reporter that writes its user-friendly output to stdout and
+uses ANSI colour codes for colouring the output.
+
+Using multiple reporters (or one reporter and one-or-more [event
+listeners](event-listener.md#top)) can have surprisingly complex semantics
+when using customization points provided to reporters by Catch2, namely
+capturing stdout/stderr from test cases.
+
+As long as at least one reporter (or listener) asks Catch2 to capture
+stdout/stderr, captured stdout and stderr will be available to all
+reporters and listeners.
+
+Because this might be surprising to the users, if at least one active
+_reporter_ is non-capturing, then Catch2 tries to roughly emulate
+non-capturing behaviour by printing out the captured stdout/stderr
+just before `testCasePartialEnded` event is sent out to the active
+reporters and listeners. This means that stdout/stderr is no longer
+printed out from tests as it is being written, but instead it is written
+out in batch after each runthrough of a test case is finished.
+
+
+
+## Writing your own reporter
+
+You can also write your own custom reporter and tell Catch2 to use it.
+When writing your reporter, you have two options:
+
+* Derive from `Catch::ReporterBase`. When doing this, you will have
+  to provide handling for all [reporter events](reporter-events.md#top).
+* Derive from one of the provided [utility reporter bases in
+  Catch2](#utility-reporter-bases).
+
+Generally we recommend doing the latter, as it is less work.
+
+Apart from overriding handling of the individual reporter events, reporters
+have access to some extra customization points, described below.
+
+
+### Utility reporter bases
+
+Catch2 currently provides two utility reporter bases:
+
+* `Catch::StreamingReporterBase`
+* `Catch::CumulativeReporterBase`
+
+`StreamingReporterBase` is useful for reporters that can format and write
+out the events as they come in. It provides (usually empty) implementation
+for all reporter events, and if you let it handle the relevant events,
+it also handles storing information about active test run and test case.
+
+`CumulativeReporterBase` is a base for reporters that need to see the whole
+test run, before they can start writing the output, such as the JUnit
+and SonarQube reporters. This post-facto approach requires the assertions
+to be stringified when it is finished, so that the assertion can be written
+out later. Because the stringification can be expensive, and not all
+cumulative reporters need the assertions, this base provides customization
+point to change whether the assertions are saved or not, separate for
+passing and failing assertions.
+
+
+_Generally we recommend that if you override a member function from either
+of the bases, you call into the base's implementation first. This is not
+necessarily in all cases, but it is safer and easier._
+
+
+Writing your own reporter then looks like this:
+
+```cpp
+#include <catch2/reporters/catch_reporter_streaming_base.hpp>
+#include <catch2/catch_test_case_info.hpp>
+#include <catch2/reporters/catch_reporter_registrars.hpp>
+
+#include <iostream>
+
+class PartialReporter : public Catch::StreamingReporterBase {
+public:
+    using StreamingReporterBase::StreamingReporterBase;
+
+    static std::string getDescription() {
+        return "Reporter for testing TestCasePartialStarting/Ended events";
+    }
+
+    void testCasePartialStarting(Catch::TestCaseInfo const& testInfo,
+                                 uint64_t partNumber) override {
+        std::cout << "TestCaseStartingPartial: " << testInfo.name << '#' << partNumber << '\n';
+    }
+
+    void testCasePartialEnded(Catch::TestCaseStats const& testCaseStats,
+                              uint64_t partNumber) override {
+        std::cout << "TestCasePartialEnded: " << testCaseStats.testInfo->name << '#' << partNumber << '\n';
+    }
+};
+
+
+CATCH_REGISTER_REPORTER("partial", PartialReporter)
+```
+
+This create a simple reporter that responds to `testCasePartial*` events,
+and calls itself "partial" reporter, so it can be invoked with
+`--reporter partial` command line flag.
+
+
+### `ReporterPreferences`
+
+Each reporter instance contains instance of `ReporterPreferences`, a type
+that holds flags for the behaviour of Catch2 when this reporter run.
+Currently there are two customization options:
+
+* `shouldRedirectStdOut` - whether the reporter wants to handle
+   writes to stdout/stderr from user code, or not. This is useful for
+   reporters that output machine-parseable output, e.g. the JUnit
+   reporter, or the XML reporter.
+* `shouldReportAllAssertions` - whether the reporter wants to handle
+  `assertionEnded` events for passing assertions as well as failing
+   assertions. Usually reporters do not report successful assertions
+   and don't need them for their output, but sometimes the desired output
+   format includes passing assertions even without the `-s` flag.
+
+
+### Per-reporter configuration
+
+> Per-reporter configuration was introduced in Catch2 3.0.1
+
+Catch2 supports some configuration to happen per reporter. The configuration
+options fall into one of two categories:
+
+* Catch2-recognized options
+* Reporter-specific options
+
+The former is a small set of universal options that Catch2 handles for
+the reporters, e.g. output file or console colour mode. The latter are
+options that the reporters have to handle themselves, but the keys and
+values can be arbitrary strings, as long as they don't contain `::`. This
+allows writing reporters that can be significantly customized at runtime.
+
+Reporter-specific options always have to be prefixed with "X" (large
+letter X).
+
+
+### Other expected functionality of a reporter
+
+When writing a custom reporter, there are few more things that you should
+keep in mind. These are not important for correctness, but they are
+important for the reporter to work _nicely_.
+
+* Catch2 provides a simple verbosity option for users. There are three
+  verbosity levels, "quiet", "normal", and "high", and if it makes sense
+  for reporter's output format, it should respond to these by changing
+  what, and how much, it writes out.
+
+* Catch2 operates with an rng-seed. Knowing what seed a test run had
+  is important if you want to replicate it, so your reporter should
+  report the rng-seed, if at all possible given the target output format.
+
+* Catch2 also operates with test filters, or test specs. If a filter
+  is present, you should also report the filter, if at all possible given
+  the target output format.
+
+
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/test-cases-and-sections.md

@@ -0,0 +1,338 @@
+<a id="top"></a>
+# Test cases and sections
+
+**Contents**<br>
+[Tags](#tags)<br>
+[Tag aliases](#tag-aliases)<br>
+[BDD-style test cases](#bdd-style-test-cases)<br>
+[Type parametrised test cases](#type-parametrised-test-cases)<br>
+[Signature based parametrised test cases](#signature-based-parametrised-test-cases)<br>
+
+While Catch fully supports the traditional, xUnit, style of class-based fixtures containing test case methods this is not the preferred style.
+
+Instead Catch provides a powerful mechanism for nesting test case sections within a test case. For a more detailed discussion see the [tutorial](tutorial.md#test-cases-and-sections).
+
+Test cases and sections are very easy to use in practice:
+
+* **TEST_CASE(** _test name_ \[, _tags_ \] **)**
+* **SECTION(** _section name_, \[, _section description_ \] **)**
+
+
+_test name_ and _section name_ are free form, quoted, strings.
+The optional _tags_ argument is a quoted string containing one or more
+tags enclosed in square brackets, and are discussed below.
+_section description_ can be used to provide long form description
+of a section while keeping the _section name_ short for use with the
+[`-c` command line parameter](command-line.md#specify-the-section-to-run).
+
+**Test names must be unique within the Catch executable.**
+
+For examples see the [Tutorial](tutorial.md#top)
+
+## Tags
+
+Tags allow an arbitrary number of additional strings to be associated with a test case. Test cases can be selected (for running, or just for listing) by tag - or even by an expression that combines several tags. At their most basic level they provide a simple way to group several related tests together.
+
+As an example - given the following test cases:
+
+    TEST_CASE( "A", "[widget]" ) { /* ... */ }
+    TEST_CASE( "B", "[widget]" ) { /* ... */ }
+    TEST_CASE( "C", "[gadget]" ) { /* ... */ }
+    TEST_CASE( "D", "[widget][gadget]" ) { /* ... */ }
+
+The tag expression, ```"[widget]"``` selects A, B & D. ```"[gadget]"``` selects C & D. ```"[widget][gadget]"``` selects just D and ```"[widget],[gadget]"``` selects all four test cases.
+
+For more detail on command line selection see [the command line docs](command-line.md#specifying-which-tests-to-run)
+
+Tag names are not case sensitive and can contain any ASCII characters.
+This means that tags `[tag with spaces]` and `[I said "good day"]`
+are both allowed tags and can be filtered on. However, escapes are not
+supported however and `[\]]` is not a valid tag.
+
+The same tag can be specified multiple times for a single test case,
+but only one of the instances of identical tags will be kept. Which one
+is kept is functionally random.
+
+
+### Special Tags
+
+All tag names beginning with non-alphanumeric characters are reserved by Catch. Catch defines a number of "special" tags, which have meaning to the test runner itself. These special tags all begin with a symbol character. Following is a list of currently defined special tags and their meanings.
+
+* `[.]` - causes test cases to be skipped from the default list (i.e. when no test cases have been explicitly selected through tag expressions or name wildcards). The hide tag is often combined with another, user, tag (for example `[.][integration]` - so all integration tests are excluded from the default run but can be run by passing `[integration]` on the command line). As a short-cut you can combine these by simply prefixing your user tag with a `.` - e.g. `[.integration]`.
+
+* `[!throws]` - lets Catch know that this test is likely to throw an exception even if successful. This causes the test to be excluded when running with `-e` or `--nothrow`.
+
+* `[!mayfail]` - doesn't fail the test if any given assertion fails (but still reports it). This can be useful to flag a work-in-progress, or a known issue that you don't want to immediately fix but still want to track in your tests.
+
+* `[!shouldfail]` - like `[!mayfail]` but *fails* the test if it *passes*. This can be useful if you want to be notified of accidental, or third-party, fixes.
+
+* `[!nonportable]` - Indicates that behaviour may vary between platforms or compilers.
+
+* `[#<filename>]` - running with `-#` or `--filenames-as-tags` causes Catch to add the filename, prefixed with `#` (and with any extension stripped), as a tag to all contained tests, e.g. tests in testfile.cpp would all be tagged `[#testfile]`.
+
+* `[@<alias>]` - tag aliases all begin with `@` (see below).
+
+* `[!benchmark]` - this test case is actually a benchmark. Currently this only serves to hide the test case by default, to avoid the execution time costs.
+
+
+## Tag aliases
+
+Between tag expressions and wildcarded test names (as well as combinations of the two) quite complex patterns can be constructed to direct which test cases are run. If a complex pattern is used often it is convenient to be able to create an alias for the expression. This can be done, in code, using the following form:
+
+    CATCH_REGISTER_TAG_ALIAS( <alias string>, <tag expression> )
+
+Aliases must begin with the `@` character. An example of a tag alias is:
+
+    CATCH_REGISTER_TAG_ALIAS( "[@nhf]", "[failing]~[.]" )
+
+Now when `[@nhf]` is used on the command line this matches all tests that are tagged `[failing]`, but which are not also hidden.
+
+## BDD-style test cases
+
+In addition to Catch's take on the classic style of test cases, Catch supports an alternative syntax that allow tests to be written as "executable specifications" (one of the early goals of [Behaviour Driven Development](http://dannorth.net/introducing-bdd/)). This set of macros map on to ```TEST_CASE```s and ```SECTION```s, with a little internal support to make them smoother to work with.
+
+* **SCENARIO(** _scenario name_ \[, _tags_ \] **)**
+
+This macro maps onto ```TEST_CASE``` and works in the same way, except that the test case name will be prefixed by "Scenario: "
+
+* **GIVEN(** _something_ **)**
+* **WHEN(** _something_ **)**
+* **THEN(** _something_ **)**
+
+These macros map onto ```SECTION```s except that the section names are the _something_ texts prefixed by
+"given: ", "when: " or "then: " respectively. These macros also map onto the AAA or A<sup>3</sup> test pattern
+(standing either for [Assemble-Activate-Assert](http://wiki.c2.com/?AssembleActivateAssert) or
+[Arrange-Act-Assert](http://wiki.c2.com/?ArrangeActAssert)), and in this context, the macros provide both code
+documentation and reporting of these parts of a test case without the need for extra comments or code to do so.
+
+Semantically, a `GIVEN` clause may have multiple _independent_ `WHEN` clauses within it. This allows a test
+to have, e.g., one set of "given" objects and multiple subtests using those objects in various ways in each
+of the `WHEN` clauses without repeating the initialisation from the `GIVEN` clause. When there are _dependent_
+clauses -- such as a second `WHEN` clause that should only happen _after_ the previous `WHEN` clause has been
+executed and validated -- there are additional macros starting with `AND_`:
+
+* **AND_GIVEN(** _something_ **)**
+* **AND_WHEN(** _something_ **)**
+* **AND_THEN(** _something_ **)**
+
+These are used to chain ```GIVEN```s, ```WHEN```s and ```THEN```s together. The `AND_*` clause is placed
+_inside_ the clause on which it depends. There can be multiple _independent_ clauses that are all _dependent_
+on a single outer clause.
+```cpp
+SCENARIO( "vector can be sized and resized" ) {
+    GIVEN( "An empty vector" ) {
+        auto v = std::vector<std::string>{};
+
+        // Validate assumption of the GIVEN clause
+        THEN( "The size and capacity start at 0" ) {
+            REQUIRE( v.size() == 0 );
+            REQUIRE( v.capacity() == 0 );
+        }
+
+        // Validate one use case for the GIVEN object
+        WHEN( "push_back() is called" ) {
+            v.push_back("hullo");
+
+            THEN( "The size changes" ) {
+                REQUIRE( v.size() == 1 );
+                REQUIRE( v.capacity() >= 1 );
+            }
+        }
+    }
+}
+```
+
+This code will result in two runs through the scenario:
+```
+Scenario : vector can be sized and resized
+  Given  : An empty vector
+  Then   : The size and capacity start at 0
+
+Scenario : vector can be sized and resized
+  Given  : An empty vector
+  When   : push_back() is called
+  Then   : The size changes
+```
+
+See also [runnable example on godbolt](https://godbolt.org/z/eY5a64r99),
+with a more complicated (and failing) example.
+
+> `AND_GIVEN` was [introduced](https://github.com/catchorg/Catch2/issues/1360) in Catch2 2.4.0.
+
+When any of these macros are used the console reporter recognises them and formats the test case header such that the Givens, Whens and Thens are aligned to aid readability.
+
+Other than the additional prefixes and the formatting in the console reporter these macros behave exactly as ```TEST_CASE```s and ```SECTION```s. As such there is nothing enforcing the correct sequencing of these macros - that's up to the programmer!
+
+## Type parametrised test cases
+
+In addition to `TEST_CASE`s, Catch2 also supports test cases parametrised
+by types, in the form of `TEMPLATE_TEST_CASE`,
+`TEMPLATE_PRODUCT_TEST_CASE` and `TEMPLATE_LIST_TEST_CASE`.
+
+* **TEMPLATE_TEST_CASE(** _test name_ , _tags_,  _type1_, _type2_, ..., _typen_ **)**
+
+> [Introduced](https://github.com/catchorg/Catch2/issues/1437) in Catch2 2.5.0.
+
+_test name_ and _tag_ are exactly the same as they are in `TEST_CASE`,
+with the difference that the tag string must be provided (however, it
+can be empty). _type1_ through _typen_ is the list of types for which
+this test case should run, and, inside the test code, the current type
+is available as the `TestType` type.
+
+Because of limitations of the C++ preprocessor, if you want to specify
+a type with multiple template parameters, you need to enclose it in
+parentheses, e.g. `std::map<int, std::string>` needs to be passed as
+`(std::map<int, std::string>)`.
+
+Example:
+```cpp
+TEMPLATE_TEST_CASE( "vectors can be sized and resized", "[vector][template]", int, std::string, (std::tuple<int,float>) ) {
+
+    std::vector<TestType> v( 5 );
+
+    REQUIRE( v.size() == 5 );
+    REQUIRE( v.capacity() >= 5 );
+
+    SECTION( "resizing bigger changes size and capacity" ) {
+        v.resize( 10 );
+
+        REQUIRE( v.size() == 10 );
+        REQUIRE( v.capacity() >= 10 );
+    }
+    SECTION( "resizing smaller changes size but not capacity" ) {
+        v.resize( 0 );
+
+        REQUIRE( v.size() == 0 );
+        REQUIRE( v.capacity() >= 5 );
+
+        SECTION( "We can use the 'swap trick' to reset the capacity" ) {
+            std::vector<TestType> empty;
+            empty.swap( v );
+
+            REQUIRE( v.capacity() == 0 );
+        }
+    }
+    SECTION( "reserving smaller does not change size or capacity" ) {
+        v.reserve( 0 );
+
+        REQUIRE( v.size() == 5 );
+        REQUIRE( v.capacity() >= 5 );
+    }
+}
+```
+
+* **TEMPLATE_PRODUCT_TEST_CASE(** _test name_ , _tags_, (_template-type1_, _template-type2_, ..., _template-typen_), (_template-arg1_, _template-arg2_, ..., _template-argm_) **)**
+
+> [Introduced](https://github.com/catchorg/Catch2/issues/1468) in Catch2 2.6.0.
+
+_template-type1_ through _template-typen_ is list of template template
+types which should be combined with each of _template-arg1_ through
+ _template-argm_, resulting in _n * m_ test cases. Inside the test case,
+the resulting type is available under the name of `TestType`.
+
+To specify more than 1 type as a single _template-type_ or _template-arg_,
+you must enclose the types in an additional set of parentheses, e.g.
+`((int, float), (char, double))` specifies 2 template-args, each
+consisting of 2 concrete types (`int`, `float` and `char`, `double`
+respectively). You can also omit the outer set of parentheses if you
+specify only one type as the full set of either the _template-types_,
+or the _template-args_.
+
+
+Example:
+```cpp
+template< typename T>
+struct Foo {
+    size_t size() {
+        return 0;
+    }
+};
+
+TEMPLATE_PRODUCT_TEST_CASE("A Template product test case", "[template][product]", (std::vector, Foo), (int, float)) {
+    TestType x;
+    REQUIRE(x.size() == 0);
+}
+```
+
+You can also have different arities in the _template-arg_ packs:
+```cpp
+TEMPLATE_PRODUCT_TEST_CASE("Product with differing arities", "[template][product]", std::tuple, (int, (int, double), (int, double, float))) {
+    TestType x;
+    REQUIRE(std::tuple_size<TestType>::value >= 1);
+}
+```
+
+* **TEMPLATE_LIST_TEST_CASE(** _test name_, _tags_, _type list_ **)**
+
+> [Introduced](https://github.com/catchorg/Catch2/issues/1627) in Catch2 2.9.0.
+
+_type list_ is a generic list of types on which test case should be instantiated.
+List can be `std::tuple`, `boost::mpl::list`, `boost::mp11::mp_list` or anything with
+`template <typename...>` signature.
+
+This allows you to reuse the _type list_ in multiple test cases.
+
+Example:
+```cpp
+using MyTypes = std::tuple<int, char, float>;
+TEMPLATE_LIST_TEST_CASE("Template test case with test types specified inside std::tuple", "[template][list]", MyTypes)
+{
+    REQUIRE(sizeof(TestType) > 0);
+}
+```
+
+
+## Signature based parametrised test cases
+
+> [Introduced](https://github.com/catchorg/Catch2/issues/1609) in Catch2 2.8.0.
+
+In addition to [type parametrised test cases](#type-parametrised-test-cases) Catch2 also supports
+signature base parametrised test cases, in form of `TEMPLATE_TEST_CASE_SIG` and `TEMPLATE_PRODUCT_TEST_CASE_SIG`.
+These test cases have similar syntax like [type parametrised test cases](#type-parametrised-test-cases), with one
+additional positional argument which specifies the signature.
+
+### Signature
+Signature has some strict rules for these tests cases to work properly:
+* signature with multiple template parameters e.g. `typename T, size_t S` must have this format in test case declaration
+  `((typename T, size_t S), T, S)`
+* signature with variadic template arguments e.g. `typename T, size_t S, typename...Ts` must have this format in test case declaration
+  `((typename T, size_t S, typename...Ts), T, S, Ts...)`
+* signature with single non type template parameter e.g. `int V` must have this format in test case declaration `((int V), V)`
+* signature with single type template parameter e.g. `typename T` should not be used as it is in fact `TEMPLATE_TEST_CASE`
+
+Currently Catch2 support up to 11 template parameters in signature
+
+### Examples
+
+* **TEMPLATE_TEST_CASE_SIG(** _test name_ , _tags_,  _signature_, _type1_, _type2_, ..., _typen_ **)**
+
+Inside `TEMPLATE_TEST_CASE_SIG` test case you can use the names of template parameters as defined in _signature_.
+
+```cpp
+TEMPLATE_TEST_CASE_SIG("TemplateTestSig: arrays can be created from NTTP arguments", "[vector][template][nttp]",
+  ((typename T, int V), T, V), (int,5), (float,4), (std::string,15), ((std::tuple<int, float>), 6)) {
+
+    std::array<T, V> v;
+    REQUIRE(v.size() > 1);
+}
+```
+
+* **TEMPLATE_PRODUCT_TEST_CASE_SIG(** _test name_ , _tags_, _signature_, (_template-type1_, _template-type2_, ..., _template-typen_), (_template-arg1_, _template-arg2_, ..., _template-argm_) **)**
+
+```cpp
+
+template<typename T, size_t S>
+struct Bar {
+    size_t size() { return S; }
+};
+
+TEMPLATE_PRODUCT_TEST_CASE_SIG("A Template product test case with array signature", "[template][product][nttp]", ((typename T, size_t S), T, S), (std::array, Bar), ((int, 9), (float, 42))) {
+    TestType x;
+    REQUIRE(x.size() > 0);
+}
+```
+
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/test-fixtures.md

@@ -0,0 +1,162 @@
+<a id="top"></a>
+# Test fixtures
+
+## Defining test fixtures
+
+Although Catch allows you to group tests together as [sections within a test case](test-cases-and-sections.md), it can still be convenient, sometimes, to group them using a more traditional test fixture. Catch fully supports this too. You define the test fixture as a simple structure:
+
+```c++
+class UniqueTestsFixture {
+  private:
+   static int uniqueID;
+  protected:
+   DBConnection conn;
+  public:
+   UniqueTestsFixture() : conn(DBConnection::createConnection("myDB")) {
+   }
+  protected:
+   int getID() {
+     return ++uniqueID;
+   }
+ };
+
+ int UniqueTestsFixture::uniqueID = 0;
+
+ TEST_CASE_METHOD(UniqueTestsFixture, "Create Employee/No Name", "[create]") {
+   REQUIRE_THROWS(conn.executeSQL("INSERT INTO employee (id, name) VALUES (?, ?)", getID(), ""));
+ }
+ TEST_CASE_METHOD(UniqueTestsFixture, "Create Employee/Normal", "[create]") {
+   REQUIRE(conn.executeSQL("INSERT INTO employee (id, name) VALUES (?, ?)", getID(), "Joe Bloggs"));
+ }
+```
+
+The two test cases here will create uniquely-named derived classes of UniqueTestsFixture and thus can access the `getID()` protected method and `conn` member variables. This ensures that both the test cases are able to create a DBConnection using the same method (DRY principle) and that any ID's created are unique such that the order that tests are executed does not matter.
+
+
+Catch2 also provides `TEMPLATE_TEST_CASE_METHOD` and
+`TEMPLATE_PRODUCT_TEST_CASE_METHOD` that can be used together
+with templated fixtures and templated template fixtures to perform
+tests for multiple different types. Unlike `TEST_CASE_METHOD`,
+`TEMPLATE_TEST_CASE_METHOD` and `TEMPLATE_PRODUCT_TEST_CASE_METHOD` do
+require the tag specification to be non-empty, as it is followed by
+further macro arguments.
+
+Also note that, because of limitations of the C++ preprocessor, if you
+want to specify a type with multiple template parameters, you need to
+enclose it in parentheses, e.g. `std::map<int, std::string>` needs to be
+passed as `(std::map<int, std::string>)`.
+In the case of `TEMPLATE_PRODUCT_TEST_CASE_METHOD`, if a member of the
+type list should consist of more than single type, it needs to be enclosed
+in another pair of parentheses, e.g. `(std::map, std::pair)` and
+`((int, float), (char, double))`.
+
+Example:
+```cpp
+template< typename T >
+struct Template_Fixture {
+    Template_Fixture(): m_a(1) {}
+
+    T m_a;
+};
+
+TEMPLATE_TEST_CASE_METHOD(Template_Fixture,
+                          "A TEMPLATE_TEST_CASE_METHOD based test run that succeeds",
+                          "[class][template]",
+                          int, float, double) {
+    REQUIRE( Template_Fixture<TestType>::m_a == 1 );
+}
+
+template<typename T>
+struct Template_Template_Fixture {
+    Template_Template_Fixture() {}
+
+    T m_a;
+};
+
+template<typename T>
+struct Foo_class {
+    size_t size() {
+        return 0;
+    }
+};
+
+TEMPLATE_PRODUCT_TEST_CASE_METHOD(Template_Template_Fixture,
+                                  "A TEMPLATE_PRODUCT_TEST_CASE_METHOD based test succeeds",
+                                  "[class][template]",
+                                  (Foo_class, std::vector),
+                                  int) {
+    REQUIRE( Template_Template_Fixture<TestType>::m_a.size() == 0 );
+}
+```
+
+_While there is an upper limit on the number of types you can specify
+in single `TEMPLATE_TEST_CASE_METHOD` or `TEMPLATE_PRODUCT_TEST_CASE_METHOD`,
+the limit is very high and should not be encountered in practice._
+
+## Signature-based parametrised test fixtures
+
+> [Introduced](https://github.com/catchorg/Catch2/issues/1609) in Catch2 2.8.0.
+
+Catch2 also provides `TEMPLATE_TEST_CASE_METHOD_SIG` and `TEMPLATE_PRODUCT_TEST_CASE_METHOD_SIG` to support
+fixtures using non-type template parameters. These test cases work similar to `TEMPLATE_TEST_CASE_METHOD` and `TEMPLATE_PRODUCT_TEST_CASE_METHOD`,
+with additional positional argument for [signature](test-cases-and-sections.md#signature-based-parametrised-test-cases).
+
+Example:
+```cpp
+template <int V>
+struct Nttp_Fixture{
+    int value = V;
+};
+
+TEMPLATE_TEST_CASE_METHOD_SIG(
+    Nttp_Fixture,
+    "A TEMPLATE_TEST_CASE_METHOD_SIG based test run that succeeds",
+    "[class][template][nttp]",
+    ((int V), V),
+    1, 3, 6) {
+    REQUIRE(Nttp_Fixture<V>::value > 0);
+}
+
+template<typename T>
+struct Template_Fixture_2 {
+    Template_Fixture_2() {}
+
+    T m_a;
+};
+
+template< typename T, size_t V>
+struct Template_Foo_2 {
+    size_t size() { return V; }
+};
+
+TEMPLATE_PRODUCT_TEST_CASE_METHOD_SIG(
+    Template_Fixture_2,
+    "A TEMPLATE_PRODUCT_TEST_CASE_METHOD_SIG based test run that succeeds",
+    "[class][template][product][nttp]",
+    ((typename T, size_t S), T, S),
+    (std::array, Template_Foo_2),
+    ((int,2), (float,6))) {
+    REQUIRE(Template_Fixture_2<TestType>{}.m_a.size() >= 2);
+}
+```
+
+## Template fixtures with types specified in template type lists
+
+Catch2 also provides `TEMPLATE_LIST_TEST_CASE_METHOD` to support template fixtures with types specified in
+template type lists like `std::tuple`, `boost::mpl::list` or `boost::mp11::mp_list`. This test case works the same as `TEMPLATE_TEST_CASE_METHOD`,
+only difference is the source of types. This allows you to reuse the template type list in multiple test cases.
+
+Example:
+```cpp
+using MyTypes = std::tuple<int, char, double>;
+TEMPLATE_LIST_TEST_CASE_METHOD(Template_Fixture,
+                               "Template test case method with test types specified inside std::tuple",
+                               "[class][template][list]",
+                               MyTypes) {
+    REQUIRE( Template_Fixture<TestType>::m_a == 1 );
+}
+```
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/tostring.md

@@ -0,0 +1,132 @@
+<a id="top"></a>
+# String conversions
+
+**Contents**<br>
+[operator << overload for std::ostream](#operator--overload-for-stdostream)<br>
+[Catch::StringMaker specialisation](#catchstringmaker-specialisation)<br>
+[Catch::is_range specialisation](#catchis_range-specialisation)<br>
+[Exceptions](#exceptions)<br>
+[Enums](#enums)<br>
+[Floating point precision](#floating-point-precision)<br>
+
+
+Catch needs to be able to convert types you use in assertions and logging expressions into strings (for logging and reporting purposes).
+Most built-in or std types are supported out of the box but there are two ways that you can tell Catch how to convert your own types (or other, third-party types) into strings.
+
+## operator << overload for std::ostream
+
+This is the standard way of providing string conversions in C++ - and the chances are you may already provide this for your own purposes. If you're not familiar with this idiom it involves writing a free function of the form:
+
+```cpp
+std::ostream& operator << ( std::ostream& os, T const& value ) {
+    os << convertMyTypeToString( value );
+    return os;
+}
+```
+
+(where ```T``` is your type and ```convertMyTypeToString``` is where you'll write whatever code is necessary to make your type printable - it doesn't have to be in another function).
+
+You should put this function in the same namespace as your type, or the global namespace, and have it declared before including Catch's header.
+
+## Catch::StringMaker specialisation
+If you don't want to provide an ```operator <<``` overload, or you want to convert your type differently for testing purposes, you can provide a specialization for `Catch::StringMaker<T>`:
+
+```cpp
+namespace Catch {
+    template<>
+    struct StringMaker<T> {
+        static std::string convert( T const& value ) {
+            return convertMyTypeToString( value );
+        }
+    };
+}
+```
+
+## Catch::is_range specialisation
+As a fallback, Catch attempts to detect if the type can be iterated
+(`begin(T)` and `end(T)` are valid) and if it can be, it is stringified
+as a range. For certain types this can lead to infinite recursion, so
+it can be disabled by specializing `Catch::is_range` like so:
+
+```cpp
+namespace Catch {
+    template<>
+    struct is_range<T> {
+        static const bool value = false;
+    };
+}
+
+```
+
+
+## Exceptions
+
+By default all exceptions deriving from `std::exception` will be translated to strings by calling the `what()` method. For exception types that do not derive from `std::exception` - or if `what()` does not return a suitable string - use `CATCH_TRANSLATE_EXCEPTION`. This defines a function that takes your exception type, by reference, and returns a string. It can appear anywhere in the code - it doesn't have to be in the same translation unit. For example:
+
+```cpp
+CATCH_TRANSLATE_EXCEPTION( MyType const& ex ) {
+    return ex.message();
+}
+```
+
+## Enums
+
+> Introduced in Catch2 2.8.0.
+
+Enums that already have a `<<` overload for `std::ostream` will convert to strings as expected.
+If you only need to convert enums to strings for test reporting purposes you can provide a `StringMaker` specialisations as any other type.
+However, as a convenience, Catch provides the `REGISTER_ENUM` helper macro that will generate the `StringMaker` specialiation for you with minimal code.
+Simply provide it the (qualified) enum name, followed by all the enum values, and you're done!
+
+E.g.
+
+```cpp
+enum class Fruits { Banana, Apple, Mango };
+
+CATCH_REGISTER_ENUM( Fruits, Fruits::Banana, Fruits::Apple, Fruits::Mango )
+
+TEST_CASE() {
+    REQUIRE( Fruits::Mango == Fruits::Apple );
+}
+```
+
+... or if the enum is in a namespace:
+```cpp
+namespace Bikeshed {
+    enum class Colours { Red, Green, Blue };
+}
+
+// Important!: This macro must appear at top level scope - not inside a namespace
+// You can fully qualify the names, or use a using if you prefer
+CATCH_REGISTER_ENUM( Bikeshed::Colours,
+    Bikeshed::Colours::Red,
+    Bikeshed::Colours::Green,
+    Bikeshed::Colours::Blue )
+
+TEST_CASE() {
+    REQUIRE( Bikeshed::Colours::Red == Bikeshed::Colours::Blue );
+}
+```
+
+## Floating point precision
+
+> [Introduced](https://github.com/catchorg/Catch2/issues/1614) in Catch2 2.8.0.
+
+Catch provides a built-in `StringMaker` specialization for both `float`
+and `double`. By default, it uses what we think is a reasonable precision,
+but you can customize it by modifying the `precision` static variable
+inside the `StringMaker` specialization, like so:
+
+```cpp
+        Catch::StringMaker<float>::precision = 15;
+        const float testFloat1 = 1.12345678901234567899f;
+        const float testFloat2 = 1.12345678991234567899f;
+        REQUIRE(testFloat1 == testFloat2);
+```
+
+This assertion will fail and print out the `testFloat1` and `testFloat2`
+to 15 decimal places.
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/tutorial.md

@@ -0,0 +1,227 @@
+<a id="top"></a>
+# Tutorial
+
+**Contents**<br>
+[Getting Catch2](#getting-catch2)<br>
+[Writing tests](#writing-tests)<br>
+[Test cases and sections](#test-cases-and-sections)<br>
+[BDD style testing](#bdd-style-testing)<br>
+[Data and Type driven tests](#data-and-type-driven-tests)<br>
+[Next steps](#next-steps)<br>
+
+
+## Getting Catch2
+
+Ideally you should be using Catch2 through its [CMake integration](cmake-integration.md#top).
+Catch2 also provides pkg-config files and two file (header + cpp)
+distribution, but this documentation will assume you are using CMake. If
+you are using the two file distribution instead, remember to replace
+the included header with `catch_amalgamated.hpp`.
+
+
+## Writing tests
+
+Let's start with a really simple example ([code](../examples/010-TestCase.cpp)). Say you have written a function to calculate factorials and now you want to test it (let's leave aside TDD for now).
+
+```c++
+unsigned int Factorial( unsigned int number ) {
+    return number <= 1 ? number : Factorial(number-1)*number;
+}
+```
+
+```c++
+#include <catch2/catch_test_macros.hpp>
+
+unsigned int Factorial( unsigned int number ) {
+    return number <= 1 ? number : Factorial(number-1)*number;
+}
+
+TEST_CASE( "Factorials are computed", "[factorial]" ) {
+    REQUIRE( Factorial(1) == 1 );
+    REQUIRE( Factorial(2) == 2 );
+    REQUIRE( Factorial(3) == 6 );
+    REQUIRE( Factorial(10) == 3628800 );
+}
+```
+
+This will compile to a complete executable which responds to [command line arguments](command-line.md#top). If you just run it with no arguments it will execute all test cases (in this case there is just one), report any failures, report a summary of how many tests passed and failed and return the number of failed tests (useful for if you just want a yes/ no answer to: "did it work").
+
+Anyway, as the tests above as written will pass, but there is a bug.
+The problem is that `Factorial(0)` should return 1 (due to [its
+definition](https://en.wikipedia.org/wiki/Factorial#Factorial_of_zero)).
+Let's add that as an assertion to the test case:
+
+```c++
+TEST_CASE( "Factorials are computed", "[factorial]" ) {
+    REQUIRE( Factorial(0) == 1 );
+    REQUIRE( Factorial(1) == 1 );
+    REQUIRE( Factorial(2) == 2 );
+    REQUIRE( Factorial(3) == 6 );
+    REQUIRE( Factorial(10) == 3628800 );
+}
+```
+
+After another compile & run cycle, we will see a test failure. The output
+will look something like:
+
+```
+Example.cpp:9: FAILED:
+  REQUIRE( Factorial(0) == 1 )
+with expansion:
+  0 == 1
+```
+
+Note that the output contains both the original expression,
+`REQUIRE( Factorial(0) == 1 )` and the actual value returned by the call
+to the `Factorial` function: `0`.
+
+We can fix this bug by slightly modifying the `Factorial` function to:
+```c++
+unsigned int Factorial( unsigned int number ) {
+  return number > 1 ? Factorial(number-1)*number : 1;
+}
+```
+
+
+### What did we do here?
+
+Although this was a simple test it's been enough to demonstrate a few
+things about how Catch2 is used. Let's take a moment to consider those
+before we move on.
+
+* We introduce test cases with the `TEST_CASE` macro. This macro takes
+  one or two string arguments - a free form test name and, optionally,
+  one or more tags (for more see [Test cases and Sections](#test-cases-and-sections)).
+* The test automatically self-registers with the test runner, and user
+  does not have do anything more to ensure that it is picked up by the test
+  framework. _Note that you can run specific test, or set of tests,
+  through the [command line](command-line.md#top)._
+* The individual test assertions are written using the `REQUIRE` macro.
+  It accepts a boolean expression, and uses expression templates to
+  internally decompose it, so that it can be individually stringified
+  on test failure.
+
+On the last point, note that there are more testing macros available,
+because not all useful checks can be expressed as a simple boolean
+expression. As an example, checking that an expression throws an exception
+is done with the `REQUIRE_THROWS` macro. More on that later.
+
+
+## Test cases and sections
+
+Like most test frameworks, Catch2 supports a class-based fixture mechanism,
+where individual tests are methods on class and setup/teardown can be
+done in constructor/destructor of the type.
+
+However, their use in Catch2 is rare, because idiomatic Catch2 tests
+instead use _sections_ to share setup and teardown code between test code.
+This is best explained through an example ([code](../examples/100-Fix-Section.cpp)):
+
+```c++
+TEST_CASE( "vectors can be sized and resized", "[vector]" ) {
+
+    std::vector<int> v( 5 );
+
+    REQUIRE( v.size() == 5 );
+    REQUIRE( v.capacity() >= 5 );
+
+    SECTION( "resizing bigger changes size and capacity" ) {
+        v.resize( 10 );
+
+        REQUIRE( v.size() == 10 );
+        REQUIRE( v.capacity() >= 10 );
+    }
+    SECTION( "resizing smaller changes size but not capacity" ) {
+        v.resize( 0 );
+
+        REQUIRE( v.size() == 0 );
+        REQUIRE( v.capacity() >= 5 );
+    }
+    SECTION( "reserving bigger changes capacity but not size" ) {
+        v.reserve( 10 );
+
+        REQUIRE( v.size() == 5 );
+        REQUIRE( v.capacity() >= 10 );
+    }
+    SECTION( "reserving smaller does not change size or capacity" ) {
+        v.reserve( 0 );
+
+        REQUIRE( v.size() == 5 );
+        REQUIRE( v.capacity() >= 5 );
+    }
+}
+```
+
+For each `SECTION` the `TEST_CASE` is executed from the start. This means
+that each section is entered with a freshly constructed vector `v`, that
+we know has size 5 and capacity at least 5, because the two assertions
+are also checked before the section is entered. Each run through a test
+case will execute one, and only one, leaf section.
+
+Section can also be nested, in which case the parent section can be
+entered multiple times, once for each leaf section. Nested sections are
+most useful when you have multiple tests that share part of the set up.
+To continue on the vector example above, you could add a check that
+`std::vector::reserve` does not remove unused excess capacity, like this:
+
+```cpp
+    SECTION( "reserving bigger changes capacity but not size" ) {
+        v.reserve( 10 );
+
+        REQUIRE( v.size() == 5 );
+        REQUIRE( v.capacity() >= 10 );
+        SECTION( "reserving down unused capacity does not change capacity" ) {
+            v.reserve( 7 );
+            REQUIRE( v.size() == 5 );
+            REQUIRE( v.capacity() >= 10 );
+        }
+    }
+```
+
+Another way to look at sections is that they are a way to define a tree
+of paths through the test. Each section represents a node, and the final
+tree is walked in depth-first manner, with each path only visiting only
+one leaf node.
+
+There is no practical limit on nesting sections, as long as your compiler
+can handle them, but keep in mind that overly nested sections can become
+unreadable. From experience, having section nest more than 3 levels is
+usually very hard to follow and not worth the removed duplication.
+
+
+## BDD style testing
+
+Catch2 also provides some basic support for BDD-style testing. There are
+macro aliases for `TEST_CASE` and `SECTIONS` that you can use so that
+the resulting tests read as BDD spec. `SCENARIO` acts as a `TEST_CASE`
+with "Scenario: " name prefix. Then there are `GIVEN`, `WHEN`, `THEN`
+(and their variants with `AND_` prefix), which act as a `SECTION`,
+similarly prefixed with the macro name.
+
+For more details on the macros look at the [test cases and
+sections](test-cases-and-sections.md#top) part of the reference docs,
+or at the [vector example done with BDD macros](../examples/120-Bdd-ScenarioGivenWhenThen.cpp).
+
+
+## Data and Type driven tests
+
+Test cases in Catch2 can also be driven by types, input data, or both
+at the same time.
+
+For more details look into the Catch2 reference, either at the
+[type parametrized test cases](test-cases-and-sections.md#type-parametrised-test-cases),
+or [data generators](generators.md#top).
+
+
+## Next steps
+
+This page is a brief introduction to get you up and running with Catch2,
+and to show the basic features of Catch2. The features mentioned here
+can get you quite far, but there are many more. However, you can read
+about these as you go, in the ever-growing [reference section](Readme.md#top)
+of the documentation.
+
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/usage-tips.md

@@ -0,0 +1,100 @@
+<a id="top"></a>
+# Best practices and other tips on using Catch2
+
+## Running tests
+
+Your tests should be run in a manner roughly equivalent with:
+
+```
+./tests --order rand --warn NoAssertions
+```
+
+Notice that all the tests are run in a large batch, their relative order
+is randomized, and that you ask Catch2 to fail test whose leaf-path
+does not contain an assertion.
+
+The reason I recommend running all your tests in the same process is that
+this exposes your tests to interference from their runs. This can be both
+positive interference, where the changes in global state from previous
+test allow later tests to pass, but also negative interference, where
+changes in global state from previous test causes later tests to fail.
+
+In my experience, interference, especially destructive interference,
+usually comes from errors in the code under test, rather than the tests
+themselves. This means that by allowing interference to happen, our tests
+can find these issues. Obviously, to shake out interference coming from
+different orderings of tests, the test order also need to be shuffled
+between runs.
+
+However, running all tests in a single batch eventually becomes impractical
+as they will take too long to run, and you will want to run your tests
+in parallel.
+
+
+<a id="parallel-tests"></a>
+## Running tests in parallel
+
+There are multiple ways of running tests in parallel, with various level
+of structure. If you are using CMake and CTest, then we provide a helper
+function [`catch_discover_tests`](cmake-integration.md#automatic-test-registration)
+that registers each Catch2 `TEST_CASE` as a single CTest test, which
+is then run in a separate process. This is an easy way to set up parallel
+tests if you are already using CMake & CTest to run your tests, but you
+will lose the advantage of running tests in batches.
+
+
+Catch2 also supports [splitting tests in a binary into multiple
+shards](command-line.md#test-sharding). This can be used by any test
+runner to run batches of tests in parallel. Do note that when selecting
+on the number of shards, you should have more shards than there are cores,
+to avoid issues with long-running tests getting accidentally grouped in
+the same shard, and causing long-tailed execution time.
+
+**Note that naively composing sharding and random ordering of tests will break.**
+
+Invoking Catch2 test executable like this
+
+```text
+./tests --order rand --shard-index 0 --shard-count 3
+./tests --order rand --shard-index 1 --shard-count 3
+./tests --order rand --shard-index 2 --shard-count 3
+```
+
+does not guarantee covering all tests inside the executable, because
+each invocation will have its own random seed, thus it will have its own
+random order of tests and thus the partitioning of tests into shards will
+be different as well.
+
+To do this properly, you need the individual shards to share the random
+seed, e.g.
+```text
+./tests --order rand --shard-index 0 --shard-count 3 --rng-seed 0xBEEF
+./tests --order rand --shard-index 1 --shard-count 3 --rng-seed 0xBEEF
+./tests --order rand --shard-index 2 --shard-count 3 --rng-seed 0xBEEF
+```
+
+Catch2 actually provides a helper to automatically register multiple shards
+as CTest tests, with shared random seed that changes each CTest invocation.
+For details look at the documentation of
+[`CatchShardTests.cmake` CMake script](cmake-integration.md#catchshardtestscmake).
+
+
+## Organizing tests into binaries
+
+Both overly large and overly small test binaries can cause issues. Overly
+large test binaries have to be recompiled and relinked often, and the
+link times are usually also long. Overly small test binaries in turn pay
+significant overhead from linking against Catch2 more often per compiled
+test case, and also make it hard/impossible to run tests in batches.
+
+Because there is no hard and fast rule for the right size of a test binary,
+I recommend having 1:1 correspondence between libraries in project and test
+binaries. (At least if it is possible, in some cases it is not.) Having
+a test binary for each library in project keeps related tests together,
+and makes tests easy to navigate by reflecting the project's organizational
+structure.
+
+
+---
+
+[Home](Readme.md#top)

externals/catch/docs/why-catch.md

@@ -0,0 +1,59 @@
+<a id="top"></a>
+# Why do we need yet another C++ test framework?
+
+Good question. For C++ there are quite a number of established frameworks,
+including (but not limited to),
+[Google Test](http://code.google.com/p/googletest/),
+[Boost.Test](http://www.boost.org/doc/libs/1_49_0/libs/test/doc/html/index.html),
+[CppUnit](http://sourceforge.net/apps/mediawiki/cppunit/index.php?title=Main_Page),
+[Cute](http://www.cute-test.com), and
+[many, many more](http://en.wikipedia.org/wiki/List_of_unit_testing_frameworks#C.2B.2B).
+
+So what does Catch2 bring to the party that differentiates it from these? Apart from the catchy name, of course.
+
+
+## Key Features
+
+* Quick and easy to get started. Just download two files, add them into your project and you're away.
+* No external dependencies. As long as you can compile C++14 and have the C++ standard library available.
+* Write test cases as, self-registering, functions (or methods, if you prefer).
+* Divide test cases into sections, each of which is run in isolation (eliminates the need for fixtures).
+* Use BDD-style Given-When-Then sections as well as traditional unit test cases.
+* Only one core assertion macro for comparisons. Standard C/C++ operators are used for the comparison - yet the full expression is decomposed and lhs and rhs values are logged.
+* Tests are named using free-form strings - no more couching names in legal identifiers.
+
+
+## Other core features
+
+* Tests can be tagged for easily running ad-hoc groups of tests.
+* Failures can (optionally) break into the debugger on common platforms.
+* Output is through modular reporter objects. Basic textual and XML reporters are included. Custom reporters can easily be added.
+* JUnit xml output is supported for integration with third-party tools, such as CI servers.
+* A default main() function is provided, but you can supply your own for complete control (e.g. integration into your own test runner GUI).
+* A command line parser is provided and can still be used if you choose to provided your own main() function.
+* Alternative assertion macro(s) report failures but don't abort the test case
+* Good set of facilities for floating point comparisons (`Catch::Approx` and full set of matchers)
+* Internal and friendly macros are isolated so name clashes can be managed
+* Data generators (data driven test support)
+* Hamcrest-style Matchers for testing complex properties
+* Microbenchmarking support
+
+
+## Who else is using Catch2?
+
+A whole lot of people. According to the 2021 JetBrains C++ ecosystem survey,
+about 11% of C++ programmers use Catch2 for unit testing, making it the
+second most popular unit testing framework.
+
+You can also take a look at the (incomplete) list of [open source projects](opensource-users.md#top)
+or the (very incomplete) list of [commercial users of Catch2](commercial-users.md#top)
+for some idea on who else also uses Catch2.
+
+---
+
+See the [tutorial](tutorial.md#top) to get more of a taste of using
+Catch2 in practice.
+
+---
+
+[Home](Readme.md#top)

externals/catch/examples/010-TestCase.cpp

@@ -0,0 +1,33 @@
+// 010-TestCase.cpp
+// And write tests in the same file:
+#include <catch2/catch_test_macros.hpp>
+
+static int Factorial( int number ) {
+   return number <= 1 ? number : Factorial( number - 1 ) * number;  // fail
+// return number <= 1 ? 1      : Factorial( number - 1 ) * number;  // pass
+}
+
+TEST_CASE( "Factorial of 0 is 1 (fail)", "[single-file]" ) {
+    REQUIRE( Factorial(0) == 1 );
+}
+
+TEST_CASE( "Factorials of 1 and higher are computed (pass)", "[single-file]" ) {
+    REQUIRE( Factorial(1) == 1 );
+    REQUIRE( Factorial(2) == 2 );
+    REQUIRE( Factorial(3) == 6 );
+    REQUIRE( Factorial(10) == 3628800 );
+}
+
+// Compile & run:
+// - g++ -std=c++14 -Wall -I$(CATCH_SINGLE_INCLUDE) -o 010-TestCase 010-TestCase.cpp && 010-TestCase --success
+// - cl -EHsc -I%CATCH_SINGLE_INCLUDE% 010-TestCase.cpp && 010-TestCase --success
+
+// Expected compact output (all assertions):
+//
+// prompt> 010-TestCase --reporter compact --success
+// 010-TestCase.cpp:14: failed: Factorial(0) == 1 for: 0 == 1
+// 010-TestCase.cpp:18: passed: Factorial(1) == 1 for: 1 == 1
+// 010-TestCase.cpp:19: passed: Factorial(2) == 2 for: 2 == 2
+// 010-TestCase.cpp:20: passed: Factorial(3) == 6 for: 6 == 6
+// 010-TestCase.cpp:21: passed: Factorial(10) == 3628800 for: 3628800 (0x375f00) == 3628800 (0x375f00)
+// Failed 1 test case, failed 1 assertion.

externals/catch/examples/020-TestCase-1.cpp

@@ -0,0 +1,29 @@
+// 020-TestCase-1.cpp
+
+#include <catch2/catch_test_macros.hpp>
+
+TEST_CASE( "1: All test cases reside in other .cpp files (empty)", "[multi-file:1]" ) {
+}
+
+// ^^^
+// Normally no TEST_CASEs in this file.
+// Here just to show there are two source files via option --list-tests.
+
+// Compile & run:
+// - g++ -std=c++14 -Wall -I$(CATCH_SINGLE_INCLUDE) -c 020-TestCase-1.cpp
+// - g++ -std=c++14 -Wall -I$(CATCH_SINGLE_INCLUDE) -o 020-TestCase TestCase-1.o 020-TestCase-2.cpp && 020-TestCase --success
+//
+// - cl -EHsc -I%CATCH_SINGLE_INCLUDE% -c 020-TestCase-1.cpp
+// - cl -EHsc -I%CATCH_SINGLE_INCLUDE% -Fe020-TestCase.exe 020-TestCase-1.obj 020-TestCase-2.cpp && 020-TestCase --success
+
+// Expected test case listing:
+//
+// prompt> 020-TestCase --list-tests *
+// Matching test cases:
+//   1: All test cases reside in other .cpp files (empty)
+//       [multi-file:1]
+//   2: Factorial of 0 is computed (fail)
+//       [multi-file:2]
+//   2: Factorials of 1 and higher are computed (pass)
+//       [multi-file:2]
+// 3 matching test cases

externals/catch/examples/020-TestCase-2.cpp

@@ -0,0 +1,33 @@
+// 020-TestCase-2.cpp
+
+// main() provided by Catch in file 020-TestCase-1.cpp.
+
+#include <catch2/catch_test_macros.hpp>
+
+static int Factorial( int number ) {
+   return number <= 1 ? number : Factorial( number - 1 ) * number;  // fail
+// return number <= 1 ? 1      : Factorial( number - 1 ) * number;  // pass
+}
+
+TEST_CASE( "2: Factorial of 0 is 1 (fail)", "[multi-file:2]" ) {
+    REQUIRE( Factorial(0) == 1 );
+}
+
+TEST_CASE( "2: Factorials of 1 and higher are computed (pass)", "[multi-file:2]" ) {
+    REQUIRE( Factorial(1) == 1 );
+    REQUIRE( Factorial(2) == 2 );
+    REQUIRE( Factorial(3) == 6 );
+    REQUIRE( Factorial(10) == 3628800 );
+}
+
+// Compile: see 020-TestCase-1.cpp
+
+// Expected compact output (all assertions):
+//
+// prompt> 020-TestCase --reporter compact --success
+// 020-TestCase-2.cpp:13: failed: Factorial(0) == 1 for: 0 == 1
+// 020-TestCase-2.cpp:17: passed: Factorial(1) == 1 for: 1 == 1
+// 020-TestCase-2.cpp:18: passed: Factorial(2) == 2 for: 2 == 2
+// 020-TestCase-2.cpp:19: passed: Factorial(3) == 6 for: 6 == 6
+// 020-TestCase-2.cpp:20: passed: Factorial(10) == 3628800 for: 3628800 (0x375f00) == 3628800 (0x375f00)
+// Failed 1 test case, failed 1 assertion.

externals/catch/examples/030-Asn-Require-Check.cpp

@@ -0,0 +1,74 @@
+// 030-Asn-Require-Check.cpp
+
+// Catch has two natural expression assertion macro's:
+// - REQUIRE() stops at first failure.
+// - CHECK() continues after failure.
+
+// There are two variants to support decomposing negated expressions:
+// - REQUIRE_FALSE() stops at first failure.
+// - CHECK_FALSE() continues after failure.
+
+// main() provided by linkage to Catch2WithMain
+
+#include <catch2/catch_test_macros.hpp>
+
+static std::string one() {
+    return "1";
+}
+
+TEST_CASE( "Assert that something is true (pass)", "[require]" ) {
+    REQUIRE( one() == "1" );
+}
+
+TEST_CASE( "Assert that something is true (fail)", "[require]" ) {
+    REQUIRE( one() == "x" );
+}
+
+TEST_CASE( "Assert that something is true (stop at first failure)", "[require]" ) {
+    WARN( "REQUIRE stops at first failure:" );
+
+    REQUIRE( one() == "x" );
+    REQUIRE( one() == "1" );
+}
+
+TEST_CASE( "Assert that something is true (continue after failure)", "[check]" ) {
+    WARN( "CHECK continues after failure:" );
+
+    CHECK(   one() == "x" );
+    REQUIRE( one() == "1" );
+}
+
+TEST_CASE( "Assert that something is false (stops at first failure)", "[require-false]" ) {
+    WARN( "REQUIRE_FALSE stops at first failure:" );
+
+    REQUIRE_FALSE( one() == "1" );
+    REQUIRE_FALSE( one() != "1" );
+}
+
+TEST_CASE( "Assert that something is false (continue after failure)", "[check-false]" ) {
+    WARN( "CHECK_FALSE continues after failure:" );
+
+    CHECK_FALSE(   one() == "1" );
+    REQUIRE_FALSE( one() != "1" );
+}
+
+// Compile & run:
+// - g++ -std=c++14 -Wall -I$(CATCH_SINGLE_INCLUDE) -o 030-Asn-Require-Check 030-Asn-Require-Check.cpp && 030-Asn-Require-Check --success
+// - cl -EHsc -I%CATCH_SINGLE_INCLUDE% 030-Asn-Require-Check.cpp && 030-Asn-Require-Check --success
+
+// Expected compact output (all assertions):
+//
+// prompt> 030-Asn-Require-Check.exe --reporter compact --success
+// 030-Asn-Require-Check.cpp:20: passed: one() == "1" for: "1" == "1"
+// 030-Asn-Require-Check.cpp:24: failed: one() == "x" for: "1" == "x"
+// 030-Asn-Require-Check.cpp:28: warning: 'REQUIRE stops at first failure:'
+// 030-Asn-Require-Check.cpp:30: failed: one() == "x" for: "1" == "x"
+// 030-Asn-Require-Check.cpp:35: warning: 'CHECK continues after failure:'
+// 030-Asn-Require-Check.cpp:37: failed: one() == "x" for: "1" == "x"
+// 030-Asn-Require-Check.cpp:38: passed: one() == "1" for: "1" == "1"
+// 030-Asn-Require-Check.cpp:42: warning: 'REQUIRE_FALSE stops at first failure:'
+// 030-Asn-Require-Check.cpp:44: failed: !(one() == "1") for: !("1" == "1")
+// 030-Asn-Require-Check.cpp:49: warning: 'CHECK_FALSE continues after failure:'
+// 030-Asn-Require-Check.cpp:51: failed: !(one() == "1") for: !("1" == "1")
+// 030-Asn-Require-Check.cpp:52: passed: !(one() != "1") for: !("1" != "1")
+// Failed 5 test cases, failed 5 assertions.

externals/catch/examples/100-Fix-Section.cpp

@@ -0,0 +1,70 @@
+// 100-Fix-Section.cpp
+
+// Catch has two ways to express fixtures:
+// - Sections (this file)
+// - Traditional class-based fixtures
+
+// main() provided by linkage to Catch2WithMain
+
+#include <catch2/catch_test_macros.hpp>
+#include <vector>
+
+TEST_CASE( "vectors can be sized and resized", "[vector]" ) {
+
+    // For each section, vector v is anew:
+
+    std::vector<int> v( 5 );
+
+    REQUIRE( v.size() == 5 );
+    REQUIRE( v.capacity() >= 5 );
+
+    SECTION( "resizing bigger changes size and capacity" ) {
+        v.resize( 10 );
+
+        REQUIRE( v.size() == 10 );
+        REQUIRE( v.capacity() >= 10 );
+    }
+    SECTION( "resizing smaller changes size but not capacity" ) {
+        v.resize( 0 );
+
+        REQUIRE( v.size() == 0 );
+        REQUIRE( v.capacity() >= 5 );
+    }
+    SECTION( "reserving bigger changes capacity but not size" ) {
+        v.reserve( 10 );
+
+        REQUIRE( v.size() == 5 );
+        REQUIRE( v.capacity() >= 10 );
+    }
+    SECTION( "reserving smaller does not change size or capacity" ) {
+        v.reserve( 0 );
+
+        REQUIRE( v.size() == 5 );
+        REQUIRE( v.capacity() >= 5 );
+    }
+}
+
+// Compile & run:
+// - g++ -std=c++14 -Wall -I$(CATCH_SINGLE_INCLUDE) -o 100-Fix-Section 100-Fix-Section.cpp && 100-Fix-Section --success
+// - cl -EHsc -I%CATCH_SINGLE_INCLUDE% 100-Fix-Section.cpp && 100-Fix-Section --success
+
+// Expected compact output (all assertions):
+//
+// prompt> 100-Fix-Section.exe --reporter compact --success
+// 100-Fix-Section.cpp:17: passed: v.size() == 5 for: 5 == 5
+// 100-Fix-Section.cpp:18: passed: v.capacity() >= 5 for: 5 >= 5
+// 100-Fix-Section.cpp:23: passed: v.size() == 10 for: 10 == 10
+// 100-Fix-Section.cpp:24: passed: v.capacity() >= 10 for: 10 >= 10
+// 100-Fix-Section.cpp:17: passed: v.size() == 5 for: 5 == 5
+// 100-Fix-Section.cpp:18: passed: v.capacity() >= 5 for: 5 >= 5
+// 100-Fix-Section.cpp:29: passed: v.size() == 0 for: 0 == 0
+// 100-Fix-Section.cpp:30: passed: v.capacity() >= 5 for: 5 >= 5
+// 100-Fix-Section.cpp:17: passed: v.size() == 5 for: 5 == 5
+// 100-Fix-Section.cpp:18: passed: v.capacity() >= 5 for: 5 >= 5
+// 100-Fix-Section.cpp:35: passed: v.size() == 5 for: 5 == 5
+// 100-Fix-Section.cpp:36: passed: v.capacity() >= 10 for: 10 >= 10
+// 100-Fix-Section.cpp:17: passed: v.size() == 5 for: 5 == 5
+// 100-Fix-Section.cpp:18: passed: v.capacity() >= 5 for: 5 >= 5
+// 100-Fix-Section.cpp:41: passed: v.size() == 5 for: 5 == 5
+// 100-Fix-Section.cpp:42: passed: v.capacity() >= 5 for: 5 >= 5
+// Passed 1 test case with 16 assertions.

externals/catch/examples/110-Fix-ClassFixture.cpp

@@ -0,0 +1,66 @@
+// 110-Fix-ClassFixture.cpp
+
+// Catch has two ways to express fixtures:
+// - Sections
+// - Traditional class-based fixtures (this file)
+
+// main() provided by linkage to Catch2WithMain
+
+#include <catch2/catch_test_macros.hpp>
+
+class DBConnection
+{
+public:
+    static DBConnection createConnection( std::string const & /*dbName*/ ) {
+        return DBConnection();
+    }
+
+    bool executeSQL( std::string const & /*query*/, int const /*id*/, std::string const & arg ) {
+        if ( arg.length() == 0 ) {
+            throw std::logic_error("empty SQL query argument");
+        }
+        return true; // ok
+    }
+};
+
+class UniqueTestsFixture
+{
+protected:
+    UniqueTestsFixture()
+    : conn( DBConnection::createConnection( "myDB" ) )
+    {}
+
+    int getID() {
+        return ++uniqueID;
+    }
+
+protected:
+    DBConnection conn;
+
+private:
+    static int uniqueID;
+};
+
+int UniqueTestsFixture::uniqueID = 0;
+
+TEST_CASE_METHOD( UniqueTestsFixture, "Create Employee/No Name", "[create]" ) {
+    REQUIRE_THROWS( conn.executeSQL( "INSERT INTO employee (id, name) VALUES (?, ?)", getID(), "") );
+}
+
+TEST_CASE_METHOD( UniqueTestsFixture, "Create Employee/Normal", "[create]" ) {
+    REQUIRE( conn.executeSQL( "INSERT INTO employee (id, name) VALUES (?, ?)", getID(), "Joe Bloggs" ) );
+}
+
+// Compile & run:
+// - g++ -std=c++14 -Wall -I$(CATCH_SINGLE_INCLUDE) -o 110-Fix-ClassFixture 110-Fix-ClassFixture.cpp && 110-Fix-ClassFixture --success
+// - cl -EHsc -I%CATCH_SINGLE_INCLUDE% 110-Fix-ClassFixture.cpp && 110-Fix-ClassFixture --success
+//
+// Compile with pkg-config:
+// - g++ -std=c++14 -Wall $(pkg-config catch2-with-main --cflags)  -o 110-Fix-ClassFixture 110-Fix-ClassFixture.cpp $(pkg-config catch2-with-main --libs)
+
+// Expected compact output (all assertions):
+//
+// prompt> 110-Fix-ClassFixture.exe --reporter compact --success
+// 110-Fix-ClassFixture.cpp:47: passed: conn.executeSQL( "INSERT INTO employee (id, name) VALUES (?, ?)", getID(), "")
+// 110-Fix-ClassFixture.cpp:51: passed: conn.executeSQL( "INSERT INTO employee (id, name) VALUES (?, ?)", getID(), "Joe Bloggs" ) for: true
+// Passed both 2 test cases with 2 assertions.

externals/catch/examples/120-Bdd-ScenarioGivenWhenThen.cpp

@@ -0,0 +1,73 @@
+// 120-Bdd-ScenarioGivenWhenThen.cpp
+
+// main() provided by linkage with Catch2WithMain
+
+#include <catch2/catch_test_macros.hpp>
+
+SCENARIO( "vectors can be sized and resized", "[vector]" ) {
+
+    GIVEN( "A vector with some items" ) {
+        std::vector<int> v( 5 );
+
+        REQUIRE( v.size() == 5 );
+        REQUIRE( v.capacity() >= 5 );
+
+        WHEN( "the size is increased" ) {
+            v.resize( 10 );
+
+            THEN( "the size and capacity change" ) {
+                REQUIRE( v.size() == 10 );
+                REQUIRE( v.capacity() >= 10 );
+            }
+        }
+        WHEN( "the size is reduced" ) {
+            v.resize( 0 );
+
+            THEN( "the size changes but not capacity" ) {
+                REQUIRE( v.size() == 0 );
+                REQUIRE( v.capacity() >= 5 );
+            }
+        }
+        WHEN( "more capacity is reserved" ) {
+            v.reserve( 10 );
+
+            THEN( "the capacity changes but not the size" ) {
+                REQUIRE( v.size() == 5 );
+                REQUIRE( v.capacity() >= 10 );
+            }
+        }
+        WHEN( "less capacity is reserved" ) {
+            v.reserve( 0 );
+
+            THEN( "neither size nor capacity are changed" ) {
+                REQUIRE( v.size() == 5 );
+                REQUIRE( v.capacity() >= 5 );
+            }
+        }
+    }
+}
+
+// Compile & run:
+// - g++ -std=c++14 -Wall -I$(CATCH_SINGLE_INCLUDE) -o 120-Bdd-ScenarioGivenWhenThen 120-Bdd-ScenarioGivenWhenThen.cpp && 120-Bdd-ScenarioGivenWhenThen --success
+// - cl -EHsc -I%CATCH_SINGLE_INCLUDE% 120-Bdd-ScenarioGivenWhenThen.cpp && 120-Bdd-ScenarioGivenWhenThen --success
+
+// Expected compact output (all assertions):
+//
+// prompt> 120-Bdd-ScenarioGivenWhenThen.exe --reporter compact --success
+// 120-Bdd-ScenarioGivenWhenThen.cpp:12: passed: v.size() == 5 for: 5 == 5
+// 120-Bdd-ScenarioGivenWhenThen.cpp:13: passed: v.capacity() >= 5 for: 5 >= 5
+// 120-Bdd-ScenarioGivenWhenThen.cpp:19: passed: v.size() == 10 for: 10 == 10
+// 120-Bdd-ScenarioGivenWhenThen.cpp:20: passed: v.capacity() >= 10 for: 10 >= 10
+// 120-Bdd-ScenarioGivenWhenThen.cpp:12: passed: v.size() == 5 for: 5 == 5
+// 120-Bdd-ScenarioGivenWhenThen.cpp:13: passed: v.capacity() >= 5 for: 5 >= 5
+// 120-Bdd-ScenarioGivenWhenThen.cpp:27: passed: v.size() == 0 for: 0 == 0
+// 120-Bdd-ScenarioGivenWhenThen.cpp:28: passed: v.capacity() >= 5 for: 5 >= 5
+// 120-Bdd-ScenarioGivenWhenThen.cpp:12: passed: v.size() == 5 for: 5 == 5
+// 120-Bdd-ScenarioGivenWhenThen.cpp:13: passed: v.capacity() >= 5 for: 5 >= 5
+// 120-Bdd-ScenarioGivenWhenThen.cpp:35: passed: v.size() == 5 for: 5 == 5
+// 120-Bdd-ScenarioGivenWhenThen.cpp:36: passed: v.capacity() >= 10 for: 10 >= 10
+// 120-Bdd-ScenarioGivenWhenThen.cpp:12: passed: v.size() == 5 for: 5 == 5
+// 120-Bdd-ScenarioGivenWhenThen.cpp:13: passed: v.capacity() >= 5 for: 5 >= 5
+// 120-Bdd-ScenarioGivenWhenThen.cpp:43: passed: v.size() == 5 for: 5 == 5
+// 120-Bdd-ScenarioGivenWhenThen.cpp:44: passed: v.capacity() >= 5 for: 5 >= 5
+// Passed 1 test case with 16 assertions.

externals/catch/examples/210-Evt-EventListeners.cpp

@@ -0,0 +1,429 @@
+// 210-Evt-EventListeners.cpp
+
+// Contents:
+// 1. Printing of listener data
+// 2. My listener and registration
+// 3. Test cases
+
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/reporters/catch_reporter_event_listener.hpp>
+#include <catch2/reporters/catch_reporter_registrars.hpp>
+#include <catch2/catch_test_case_info.hpp>
+#include <iostream>
+
+// -----------------------------------------------------------------------
+// 1. Printing of listener data:
+//
+
+
+namespace {
+std::string ws(int const level) {
+    return std::string( 2 * level, ' ' );
+}
+
+std::ostream& operator<<(std::ostream& out, Catch::Tag t) {
+    return out << "original: " << t.original;
+}
+
+template< typename T >
+std::ostream& operator<<( std::ostream& os, std::vector<T> const& v ) {
+    os << "{ ";
+    for ( const auto& x : v )
+        os << x << ", ";
+    return os << "}";
+}
+// struct SourceLineInfo {
+//     char const* file;
+//     std::size_t line;
+// };
+
+void print( std::ostream& os, int const level, std::string const& title, Catch::SourceLineInfo const& info ) {
+    os << ws(level  ) << title << ":\n"
+       << ws(level+1) << "- file: " << info.file << "\n"
+       << ws(level+1) << "- line: " << info.line << "\n";
+}
+
+//struct MessageInfo {
+//    std::string macroName;
+//    std::string message;
+//    SourceLineInfo lineInfo;
+//    ResultWas::OfType type;
+//    unsigned int sequence;
+//};
+
+void print( std::ostream& os, int const level, Catch::MessageInfo const& info ) {
+    os << ws(level+1) << "- macroName: '" << info.macroName << "'\n"
+       << ws(level+1) << "- message '"    << info.message   << "'\n";
+    print( os,level+1  , "- lineInfo", info.lineInfo );
+    os << ws(level+1) << "- sequence "    << info.sequence  << "\n";
+}
+
+void print( std::ostream& os, int const level, std::string const& title, std::vector<Catch::MessageInfo> const& v ) {
+    os << ws(level  ) << title << ":\n";
+    for ( const auto& x : v )
+    {
+        os << ws(level+1) << "{\n";
+        print( os, level+2, x );
+        os << ws(level+1) << "}\n";
+    }
+//    os << ws(level+1) << "\n";
+}
+
+// struct TestRunInfo {
+//     std::string name;
+// };
+
+void print( std::ostream& os, int const level, std::string const& title, Catch::TestRunInfo const& info ) {
+    os << ws(level  ) << title << ":\n"
+       << ws(level+1) << "- name: " << info.name << "\n";
+}
+
+// struct Counts {
+//     std::size_t total() const;
+//     bool allPassed() const;
+//     bool allOk() const;
+//
+//     std::size_t passed = 0;
+//     std::size_t failed = 0;
+//     std::size_t failedButOk = 0;
+// };
+
+void print( std::ostream& os, int const level, std::string const& title, Catch::Counts const& info ) {
+    os << ws(level  ) << title << ":\n"
+       << ws(level+1) << "- total(): "     << info.total()     << "\n"
+       << ws(level+1) << "- allPassed(): " << info.allPassed() << "\n"
+       << ws(level+1) << "- allOk(): "     << info.allOk()     << "\n"
+       << ws(level+1) << "- passed: "      << info.passed      << "\n"
+       << ws(level+1) << "- failed: "      << info.failed      << "\n"
+       << ws(level+1) << "- failedButOk: " << info.failedButOk << "\n";
+}
+
+// struct Totals {
+//     Counts assertions;
+//     Counts testCases;
+// };
+
+void print( std::ostream& os, int const level, std::string const& title, Catch::Totals const& info ) {
+    os << ws(level) << title << ":\n";
+    print( os, level+1, "- assertions", info.assertions );
+    print( os, level+1, "- testCases" , info.testCases  );
+}
+
+// struct TestRunStats {
+//     TestRunInfo runInfo;
+//     Totals totals;
+//     bool aborting;
+// };
+
+void print( std::ostream& os, int const level, std::string const& title, Catch::TestRunStats const& info ) {
+    os << ws(level) << title << ":\n";
+    print( os, level+1 , "- runInfo", info.runInfo );
+    print( os, level+1 , "- totals" , info.totals  );
+    os << ws(level+1) << "- aborting: " << info.aborting << "\n";
+}
+
+//    struct Tag {
+//        StringRef original, lowerCased;
+//    };
+//
+//
+//    enum class TestCaseProperties : uint8_t {
+//        None = 0,
+//        IsHidden = 1 << 1,
+//        ShouldFail = 1 << 2,
+//        MayFail = 1 << 3,
+//        Throws = 1 << 4,
+//        NonPortable = 1 << 5,
+//        Benchmark = 1 << 6
+//    };
+//
+//
+//    struct TestCaseInfo : NonCopyable {
+//
+//        bool isHidden() const;
+//        bool throws() const;
+//        bool okToFail() const;
+//        bool expectedToFail() const;
+//
+//
+//        std::string name;
+//        std::string className;
+//        std::vector<Tag> tags;
+//        SourceLineInfo lineInfo;
+//        TestCaseProperties properties = TestCaseProperties::None;
+//    };
+
+void print( std::ostream& os, int const level, std::string const& title, Catch::TestCaseInfo const& info ) {
+    os << ws(level  ) << title << ":\n"
+       << ws(level+1) << "- isHidden(): "       << info.isHidden() << "\n"
+       << ws(level+1) << "- throws(): "         << info.throws() << "\n"
+       << ws(level+1) << "- okToFail(): "       << info.okToFail() << "\n"
+       << ws(level+1) << "- expectedToFail(): " << info.expectedToFail() << "\n"
+       << ws(level+1) << "- tagsAsString(): '"  << info.tagsAsString() << "'\n"
+       << ws(level+1) << "- name: '"            << info.name << "'\n"
+       << ws(level+1) << "- className: '"       << info.className << "'\n"
+       << ws(level+1) << "- tags: "             << info.tags << "\n";
+    print( os, level+1 , "- lineInfo", info.lineInfo );
+    os << ws(level+1) << "- properties (flags): 0x" << std::hex << static_cast<uint32_t>(info.properties) << std::dec << "\n";
+}
+
+// struct TestCaseStats {
+//     TestCaseInfo testInfo;
+//     Totals totals;
+//     std::string stdOut;
+//     std::string stdErr;
+//     bool aborting;
+// };
+
+void print( std::ostream& os, int const level, std::string const& title, Catch::TestCaseStats const& info ) {
+    os << ws(level  ) << title << ":\n";
+    print( os, level+1 , "- testInfo", *info.testInfo );
+    print( os, level+1 , "- totals"  , info.totals   );
+    os << ws(level+1) << "- stdOut: "   << info.stdOut << "\n"
+       << ws(level+1) << "- stdErr: "   << info.stdErr << "\n"
+       << ws(level+1) << "- aborting: " << info.aborting << "\n";
+}
+
+// struct SectionInfo {
+//     std::string name;
+//     std::string description;
+//     SourceLineInfo lineInfo;
+// };
+
+void print( std::ostream& os, int const level, std::string const& title, Catch::SectionInfo const& info ) {
+    os << ws(level  ) << title << ":\n"
+       << ws(level+1) << "- name: "         << info.name << "\n";
+    print( os, level+1 , "- lineInfo", info.lineInfo );
+}
+
+// struct SectionStats {
+//     SectionInfo sectionInfo;
+//     Counts assertions;
+//     double durationInSeconds;
+//     bool missingAssertions;
+// };
+
+void print( std::ostream& os, int const level, std::string const& title, Catch::SectionStats const& info ) {
+    os << ws(level  ) << title << ":\n";
+    print( os, level+1 , "- sectionInfo", info.sectionInfo );
+    print( os, level+1 , "- assertions" , info.assertions );
+    os << ws(level+1) << "- durationInSeconds: " << info.durationInSeconds << "\n"
+       << ws(level+1) << "- missingAssertions: " << info.missingAssertions << "\n";
+}
+
+// struct AssertionInfo
+// {
+//     StringRef macroName;
+//     SourceLineInfo lineInfo;
+//     StringRef capturedExpression;
+//     ResultDisposition::Flags resultDisposition;
+// };
+
+void print( std::ostream& os, int const level, std::string const& title, Catch::AssertionInfo const& info ) {
+    os << ws(level  ) << title << ":\n"
+       << ws(level+1) << "- macroName: '"  << info.macroName << "'\n";
+    print( os, level+1 , "- lineInfo" , info.lineInfo );
+    os << ws(level+1) << "- capturedExpression: '" << info.capturedExpression << "'\n"
+       << ws(level+1) << "- resultDisposition (flags): 0x" << std::hex << info.resultDisposition  << std::dec << "\n";
+}
+
+//struct AssertionResultData
+//{
+//    std::string reconstructExpression() const;
+//
+//    std::string message;
+//    mutable std::string reconstructedExpression;
+//    LazyExpression lazyExpression;
+//    ResultWas::OfType resultType;
+//};
+
+void print( std::ostream& os, int const level, std::string const& title, Catch::AssertionResultData const& info ) {
+    os << ws(level  ) << title << ":\n"
+       << ws(level+1) << "- reconstructExpression(): '" <<   info.reconstructExpression() << "'\n"
+       << ws(level+1) << "- message: '"                 <<   info.message << "'\n"
+       << ws(level+1) << "- lazyExpression: '"          << "(info.lazyExpression)" << "'\n"
+       << ws(level+1) << "- resultType: '"              <<   info.resultType << "'\n";
+}
+
+//class AssertionResult {
+//    bool isOk() const;
+//    bool succeeded() const;
+//    ResultWas::OfType getResultType() const;
+//    bool hasExpression() const;
+//    bool hasMessage() const;
+//    std::string getExpression() const;
+//    std::string getExpressionInMacro() const;
+//    bool hasExpandedExpression() const;
+//    std::string getExpandedExpression() const;
+//    std::string getMessage() const;
+//    SourceLineInfo getSourceInfo() const;
+//    std::string getTestMacroName() const;
+//
+//    AssertionInfo m_info;
+//    AssertionResultData m_resultData;
+//};
+
+void print( std::ostream& os, int const level, std::string const& title, Catch::AssertionResult const& info ) {
+    os << ws(level  ) << title << ":\n"
+       << ws(level+1) << "- isOk(): "  << info.isOk() << "\n"
+       << ws(level+1) << "- succeeded(): "  << info.succeeded() << "\n"
+       << ws(level+1) << "- getResultType(): "  << info.getResultType() << "\n"
+       << ws(level+1) << "- hasExpression(): "  << info.hasExpression() << "\n"
+       << ws(level+1) << "- hasMessage(): "  << info.hasMessage() << "\n"
+       << ws(level+1) << "- getExpression(): '"  << info.getExpression() << "'\n"
+       << ws(level+1) << "- getExpressionInMacro(): '"  << info.getExpressionInMacro()  << "'\n"
+       << ws(level+1) << "- hasExpandedExpression(): "  << info.hasExpandedExpression() << "\n"
+       << ws(level+1) << "- getExpandedExpression(): "  << info.getExpandedExpression() << "'\n"
+       << ws(level+1) << "- getMessage(): '"  << info.getMessage() << "'\n";
+    print( os, level+1 , "- getSourceInfo(): ", info.getSourceInfo() );
+    os << ws(level+1) << "- getTestMacroName(): '"  << info.getTestMacroName() << "'\n";
+
+    print( os, level+1 , "- *** m_info (AssertionInfo)", info.m_info );
+    print( os, level+1 , "- *** m_resultData (AssertionResultData)", info.m_resultData );
+}
+
+// struct AssertionStats {
+//     AssertionResult assertionResult;
+//     std::vector<MessageInfo> infoMessages;
+//     Totals totals;
+// };
+
+void print( std::ostream& os, int const level, std::string const& title, Catch::AssertionStats const& info ) {
+    os << ws(level  ) << title << ":\n";
+    print( os, level+1 , "- assertionResult", info.assertionResult );
+    print( os, level+1 , "- infoMessages", info.infoMessages );
+    print( os, level+1 , "- totals", info.totals );
+}
+
+// -----------------------------------------------------------------------
+// 2. My listener and registration:
+//
+
+char const * dashed_line =
+    "--------------------------------------------------------------------------";
+
+
+struct MyListener : Catch::EventListenerBase {
+
+    using EventListenerBase::EventListenerBase; // inherit constructor
+
+    // Get rid of Wweak-tables
+    ~MyListener() override;
+
+    // The whole test run starting
+    void testRunStarting( Catch::TestRunInfo const& testRunInfo ) override {
+        std::cout
+            << std::boolalpha
+            << "\nEvent: testRunStarting:\n";
+        print( std::cout, 1, "- testRunInfo", testRunInfo );
+    }
+
+    // The whole test run ending
+    void testRunEnded( Catch::TestRunStats const& testRunStats ) override {
+        std::cout
+            << dashed_line
+            << "\nEvent: testRunEnded:\n";
+        print( std::cout, 1, "- testRunStats", testRunStats );
+    }
+
+    // A test is being skipped (because it is "hidden")
+    void skipTest( Catch::TestCaseInfo const& testInfo ) override {
+        std::cout
+            << dashed_line
+            << "\nEvent: skipTest:\n";
+        print( std::cout, 1, "- testInfo", testInfo );
+    }
+
+    // Test cases starting
+    void testCaseStarting( Catch::TestCaseInfo const& testInfo ) override {
+        std::cout
+            << dashed_line
+            << "\nEvent: testCaseStarting:\n";
+        print( std::cout, 1, "- testInfo", testInfo );
+    }
+
+    // Test cases ending
+    void testCaseEnded( Catch::TestCaseStats const& testCaseStats ) override {
+        std::cout << "\nEvent: testCaseEnded:\n";
+        print( std::cout, 1, "testCaseStats", testCaseStats );
+    }
+
+    // Sections starting
+    void sectionStarting( Catch::SectionInfo const& sectionInfo ) override {
+        std::cout << "\nEvent: sectionStarting:\n";
+        print( std::cout, 1, "- sectionInfo", sectionInfo );
+    }
+
+    // Sections ending
+    void sectionEnded( Catch::SectionStats const& sectionStats ) override {
+        std::cout << "\nEvent: sectionEnded:\n";
+        print( std::cout, 1, "- sectionStats", sectionStats );
+    }
+
+    // Assertions before/ after
+    void assertionStarting( Catch::AssertionInfo const& assertionInfo ) override {
+        std::cout << "\nEvent: assertionStarting:\n";
+        print( std::cout, 1, "- assertionInfo", assertionInfo );
+    }
+
+    void assertionEnded( Catch::AssertionStats const& assertionStats ) override {
+        std::cout << "\nEvent: assertionEnded:\n";
+        print( std::cout, 1, "- assertionStats", assertionStats );
+    }
+};
+
+} // end anonymous namespace
+
+CATCH_REGISTER_LISTENER( MyListener )
+
+// Get rid of Wweak-tables
+MyListener::~MyListener() {}
+
+
+// -----------------------------------------------------------------------
+// 3. Test cases:
+//
+
+TEST_CASE( "1: Hidden testcase", "[.hidden]" ) {
+}
+
+TEST_CASE( "2: Testcase with sections", "[tag-A][tag-B]" ) {
+
+    int i = 42;
+
+    REQUIRE( i == 42 );
+
+    SECTION("Section 1") {
+        INFO("Section 1");
+        i = 7;
+        SECTION("Section 1.1") {
+            INFO("Section 1.1");
+            REQUIRE( i == 42 );
+        }
+    }
+
+    SECTION("Section 2") {
+        INFO("Section 2");
+        REQUIRE( i == 42 );
+    }
+    WARN("At end of test case");
+}
+
+struct Fixture {
+    int fortytwo() const {
+        return 42;
+    }
+};
+
+TEST_CASE_METHOD( Fixture, "3: Testcase with class-based fixture", "[tag-C][tag-D]" ) {
+    REQUIRE( fortytwo() == 42 );
+}
+
+// Compile & run:
+// - g++ -std=c++14 -Wall -I$(CATCH_SINGLE_INCLUDE) -o 210-Evt-EventListeners 210-Evt-EventListeners.cpp && 210-Evt-EventListeners --success
+// - cl -EHsc -I%CATCH_SINGLE_INCLUDE% 210-Evt-EventListeners.cpp && 210-Evt-EventListeners --success
+
+// Expected compact output (all assertions):
+//
+// prompt> 210-Evt-EventListeners --reporter compact --success
+// result omitted for brevity.

externals/catch/examples/231-Cfg-OutputStreams.cpp

@@ -0,0 +1,55 @@
+// 231-Cfg-OutputStreams.cpp
+// Show how to replace the streams with a simple custom made streambuf.
+
+// Note that this reimplementation _does not_ follow `std::cerr`
+// semantic, because it buffers the output. For most uses however,
+// there is no important difference between having `std::cerr` buffered
+// or unbuffered.
+#include <catch2/catch_test_macros.hpp>
+
+#include <sstream>
+#include <cstdio>
+
+class out_buff : public std::stringbuf {
+    std::FILE* m_stream;
+public:
+    out_buff(std::FILE* stream):m_stream(stream) {}
+    ~out_buff();
+    int sync() override {
+        int ret = 0;
+        for (unsigned char c : str()) {
+            if (putc(c, m_stream) == EOF) {
+                ret = -1;
+                break;
+            }
+        }
+        // Reset the buffer to avoid printing it multiple times
+        str("");
+        return ret;
+    }
+};
+
+out_buff::~out_buff() { pubsync(); }
+
+#if defined(__clang__)
+#pragma clang diagnostic ignored "-Wexit-time-destructors" // static variables in cout/cerr/clog
+#endif
+
+namespace Catch {
+    std::ostream& cout() {
+        static std::ostream ret(new out_buff(stdout));
+        return ret;
+    }
+    std::ostream& clog() {
+        static std::ostream ret(new out_buff(stderr));
+        return ret;
+    }
+    std::ostream& cerr() {
+        return clog();
+    }
+}
+
+
+TEST_CASE("This binary uses putc to write out output", "[compilation-only]") {
+    SUCCEED("Nothing to test.");
+}

externals/catch/examples/300-Gen-OwnGenerator.cpp

@@ -0,0 +1,69 @@
+// 300-Gen-OwnGenerator.cpp
+// Shows how to define a custom generator.
+
+// Specifically we will implement a random number generator for integers
+// It will have infinite capacity and settable lower/upper bound
+
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/generators/catch_generators.hpp>
+#include <catch2/generators/catch_generators_adapters.hpp>
+
+#include <random>
+
+namespace {
+
+// This class shows how to implement a simple generator for Catch tests
+class RandomIntGenerator : public Catch::Generators::IGenerator<int> {
+    std::minstd_rand m_rand;
+    std::uniform_int_distribution<> m_dist;
+    int current_number;
+public:
+
+    RandomIntGenerator(int low, int high):
+        m_rand(std::random_device{}()),
+        m_dist(low, high)
+    {
+        static_cast<void>(next());
+    }
+
+    int const& get() const override;
+    bool next() override {
+        current_number = m_dist(m_rand);
+        return true;
+    }
+};
+
+// Avoids -Wweak-vtables
+int const& RandomIntGenerator::get() const {
+    return current_number;
+}
+
+// This helper function provides a nicer UX when instantiating the generator
+// Notice that it returns an instance of GeneratorWrapper<int>, which
+// is a value-wrapper around std::unique_ptr<IGenerator<int>>.
+Catch::Generators::GeneratorWrapper<int> random(int low, int high) {
+    return Catch::Generators::GeneratorWrapper<int>(
+        new RandomIntGenerator(low, high)
+        // Another possibility:
+        // Catch::Detail::make_unique<RandomIntGenerator>(low, high)
+    );
+}
+
+} // end anonymous namespaces
+
+// The two sections in this test case are equivalent, but the first one
+// is much more readable/nicer to use
+TEST_CASE("Generating random ints", "[example][generator]") {
+    SECTION("Nice UX") {
+        auto i = GENERATE(take(100, random(-100, 100)));
+        REQUIRE(i >= -100);
+        REQUIRE(i <= 100);
+    }
+    SECTION("Creating the random generator directly") {
+        auto i = GENERATE(take(100, GeneratorWrapper<int>(Catch::Detail::make_unique<RandomIntGenerator>(-100, 100))));
+        REQUIRE(i >= -100);
+        REQUIRE(i <= 100);
+    }
+}
+
+// Compiling and running this file will result in 400 successful assertions

externals/catch/examples/301-Gen-MapTypeConversion.cpp

@@ -0,0 +1,60 @@
+// 301-Gen-MapTypeConversion.cpp
+// Shows how to use map to modify generator's return type.
+
+// Specifically we wrap a std::string returning generator with a generator
+// that converts the strings using stoi, so the returned type is actually
+// an int.
+
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/generators/catch_generators_adapters.hpp>
+
+#include <string>
+#include <sstream>
+
+namespace {
+
+// Returns a line from a stream. You could have it e.g. read lines from
+// a file, but to avoid problems with paths in examples, we will use
+// a fixed stringstream.
+class LineGenerator : public Catch::Generators::IGenerator<std::string> {
+    std::string m_line;
+    std::stringstream m_stream;
+public:
+    LineGenerator() {
+        m_stream.str("1\n2\n3\n4\n");
+        if (!next()) {
+            Catch::Generators::Detail::throw_generator_exception("Couldn't read a single line");
+        }
+    }
+
+    std::string const& get() const override;
+
+    bool next() override {
+        return !!std::getline(m_stream, m_line);
+    }
+};
+
+std::string const& LineGenerator::get() const {
+    return m_line;
+}
+
+// This helper function provides a nicer UX when instantiating the generator
+// Notice that it returns an instance of GeneratorWrapper<std::string>, which
+// is a value-wrapper around std::unique_ptr<IGenerator<std::string>>.
+Catch::Generators::GeneratorWrapper<std::string> lines(std::string /* ignored for example */) {
+    return Catch::Generators::GeneratorWrapper<std::string>(
+        new LineGenerator()
+    );
+}
+
+} // end anonymous namespace
+
+
+TEST_CASE("filter can convert types inside the generator expression", "[example][generator]") {
+    auto num = GENERATE(map<int>([](std::string const& line) { return std::stoi(line); },
+                                 lines("fake-file")));
+
+    REQUIRE(num > 0);
+}
+
+// Compiling and running this file will result in 4 successful assertions

externals/catch/examples/302-Gen-Table.cpp

@@ -0,0 +1,55 @@
+// 302-Gen-Table.cpp
+// Shows how to use table to run a test many times with different inputs. Lifted from examples on
+// issue #850.
+
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/generators/catch_generators.hpp>
+#include <string>
+
+struct TestSubject {
+    // this is the method we are going to test. It returns the length of the
+    // input string.
+    size_t GetLength( const std::string& input ) const { return input.size(); }
+};
+
+
+TEST_CASE("Table allows pre-computed test inputs and outputs", "[example][generator]") {
+    using std::make_tuple;
+    // do setup here as normal
+    TestSubject subj;
+
+    SECTION("This section is run for each row in the table") {
+        std::string test_input;
+        size_t expected_output;
+        std::tie( test_input, expected_output ) =
+            GENERATE( table<std::string, size_t>(
+                { /* In this case one of the parameters to our test case is the
+                   * expected output, but this is not required. There could be
+                   * multiple expected values in the table, which can have any
+                   * (fixed) number of columns.
+                   */
+                  make_tuple( "one", 3 ),
+                  make_tuple( "two", 3 ),
+                  make_tuple( "three", 5 ),
+                  make_tuple( "four", 4 ) } ) );
+
+        // run the test
+        auto result = subj.GetLength(test_input);
+        // capture the input data to go with the outputs.
+        CAPTURE(test_input);
+        // check it matches the pre-calculated data
+        REQUIRE(result == expected_output);
+    }   // end section
+}
+
+/* Possible simplifications where less legacy toolchain support is needed:
+ *
+ * - With libstdc++6 or newer, the make_tuple() calls can be ommitted
+ * (technically C++17 but does not require -std in GCC/Clang). See
+ *   https://stackoverflow.com/questions/12436586/tuple-vector-and-initializer-list
+ *
+ * - In C++17 mode std::tie() and the preceding variable delcarations can be
+ * replaced by structured bindings: auto [test_input, expected] = GENERATE(
+ * table<std::string, size_t>({ ...
+ */
+// Compiling and running this file will result in 4 successful assertions

externals/catch/examples/310-Gen-VariablesInGenerators.cpp

@@ -0,0 +1,35 @@
+// 310-Gen-VariablesInGenerator.cpp
+// Shows how to use variables when creating generators.
+
+// Note that using variables inside generators is dangerous and should
+// be done only if you know what you are doing, because the generators
+// _WILL_ outlive the variables -- thus they should be either captured
+// by value directly, or copied by the generators during construction.
+
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/generators/catch_generators_adapters.hpp>
+#include <catch2/generators/catch_generators_random.hpp>
+
+TEST_CASE("Generate random doubles across different ranges",
+          "[generator][example][advanced]") {
+    // Workaround for old libstdc++
+    using record = std::tuple<double, double>;
+    // Set up 3 ranges to generate numbers from
+    auto r = GENERATE(table<double, double>({
+        record{3, 4},
+        record{-4, -3},
+        record{10, 1000}
+    }));
+
+    // This will not compile (intentionally), because it accesses a variable
+    // auto number = GENERATE(take(50, random(std::get<0>(r), std::get<1>(r))));
+
+   // GENERATE_COPY copies all variables mentioned inside the expression
+   // thus this will work.
+    auto number = GENERATE_COPY(take(50, random(std::get<0>(r), std::get<1>(r))));
+
+    REQUIRE(std::abs(number) > 0);
+}
+
+// Compiling and running this file will result in 150 successful assertions
+

externals/catch/examples/311-Gen-CustomCapture.cpp

@@ -0,0 +1,43 @@
+// 311-Gen-CustomCapture.cpp
+// Shows how to provide custom capture list to the generator expression
+
+// Note that using variables inside generators is dangerous and should
+// be done only if you know what you are doing, because the generators
+// _WILL_ outlive the variables. Also, even if you know what you are
+// doing, you should probably use GENERATE_COPY or GENERATE_REF macros
+// instead. However, if your use case requires having a
+// per-variable custom capture list, this example shows how to achieve
+// that.
+
+#include <catch2/catch_test_macros.hpp>
+#include <catch2/generators/catch_generators_adapters.hpp>
+#include <catch2/generators/catch_generators_random.hpp>
+
+TEST_CASE("Generate random doubles across different ranges",
+          "[generator][example][advanced]") {
+    // Workaround for old libstdc++
+    using record = std::tuple<double, double>;
+    // Set up 3 ranges to generate numbers from
+    auto r1 = GENERATE(table<double, double>({
+        record{3, 4},
+        record{-4, -3},
+        record{10, 1000}
+    }));
+
+    auto r2(r1);
+
+    // This will take r1 by reference and r2 by value.
+    // Note that there are no advantages for doing so in this example,
+    // it is done only for expository purposes.
+    auto number = Catch::Generators::generate( "custom capture generator", CATCH_INTERNAL_LINEINFO,
+        [&r1, r2]{
+            using namespace Catch::Generators;
+            return makeGenerators(take(50, random(std::get<0>(r1), std::get<1>(r2))));
+        }
+    );
+
+    REQUIRE(std::abs(number) > 0);
+}
+
+// Compiling and running this file will result in 150 successful assertions
+

externals/catch/examples/CMakeLists.txt

@@ -0,0 +1,61 @@
+cmake_minimum_required( VERSION 3.10 )
+
+project( Catch2Examples LANGUAGES CXX )
+
+message( STATUS "Examples included" )
+
+
+# Some one-offs first:
+# 1) Tests and main in one file
+add_executable( 010-TestCase
+  010-TestCase.cpp
+)
+
+# 2) Tests and main across two files
+add_executable( 020-MultiFile
+  020-TestCase-1.cpp
+  020-TestCase-2.cpp
+)
+
+add_executable(231-Cfg_OutputStreams
+    231-Cfg-OutputStreams.cpp
+)
+target_link_libraries(231-Cfg_OutputStreams Catch2_buildall_interface)
+target_compile_definitions(231-Cfg_OutputStreams PUBLIC CATCH_CONFIG_NOSTDOUT)
+
+# These examples use the standard separate compilation
+set( SOURCES_IDIOMATIC_EXAMPLES
+    030-Asn-Require-Check.cpp
+    100-Fix-Section.cpp
+    110-Fix-ClassFixture.cpp
+    120-Bdd-ScenarioGivenWhenThen.cpp
+    210-Evt-EventListeners.cpp
+    300-Gen-OwnGenerator.cpp
+    301-Gen-MapTypeConversion.cpp
+    302-Gen-Table.cpp
+    310-Gen-VariablesInGenerators.cpp
+    311-Gen-CustomCapture.cpp
+)
+
+string( REPLACE ".cpp" "" BASENAMES_IDIOMATIC_EXAMPLES "${SOURCES_IDIOMATIC_EXAMPLES}" )
+set( TARGETS_IDIOMATIC_EXAMPLES ${BASENAMES_IDIOMATIC_EXAMPLES} )
+
+
+foreach( name ${TARGETS_IDIOMATIC_EXAMPLES} )
+    add_executable( ${name}
+      ${EXAMPLES_DIR}/${name}.cpp )
+endforeach()
+
+set(ALL_EXAMPLE_TARGETS
+  ${TARGETS_IDIOMATIC_EXAMPLES}
+  010-TestCase
+  020-MultiFile
+)
+
+foreach( name ${ALL_EXAMPLE_TARGETS} )
+    target_link_libraries( ${name} Catch2 Catch2WithMain )
+endforeach()
+
+
+list(APPEND CATCH_WARNING_TARGETS ${ALL_EXAMPLE_TARGETS})
+set(CATCH_WARNING_TARGETS ${CATCH_WARNING_TARGETS} PARENT_SCOPE)

externals/catch/extras/Catch.cmake

@@ -0,0 +1,220 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+#[=======================================================================[.rst:
+Catch
+-----
+
+This module defines a function to help use the Catch test framework.
+
+The :command:`catch_discover_tests` discovers tests by asking the compiled test
+executable to enumerate its tests.  This does not require CMake to be re-run
+when tests change.  However, it may not work in a cross-compiling environment,
+and setting test properties is less convenient.
+
+This command is intended to replace use of :command:`add_test` to register
+tests, and will create a separate CTest test for each Catch test case.  Note
+that this is in some cases less efficient, as common set-up and tear-down logic
+cannot be shared by multiple test cases executing in the same instance.
+However, it provides more fine-grained pass/fail information to CTest, which is
+usually considered as more beneficial.  By default, the CTest test name is the
+same as the Catch name; see also ``TEST_PREFIX`` and ``TEST_SUFFIX``.
+
+.. command:: catch_discover_tests
+
+  Automatically add tests with CTest by querying the compiled test executable
+  for available tests::
+
+    catch_discover_tests(target
+                         [TEST_SPEC arg1...]
+                         [EXTRA_ARGS arg1...]
+                         [WORKING_DIRECTORY dir]
+                         [TEST_PREFIX prefix]
+                         [TEST_SUFFIX suffix]
+                         [PROPERTIES name1 value1...]
+                         [TEST_LIST var]
+                         [REPORTER reporter]
+                         [OUTPUT_DIR dir]
+                         [OUTPUT_PREFIX prefix}
+                         [OUTPUT_SUFFIX suffix]
+    )
+
+  ``catch_discover_tests`` sets up a post-build command on the test executable
+  that generates the list of tests by parsing the output from running the test
+  with the ``--list-test-names-only`` argument.  This ensures that the full
+  list of tests is obtained.  Since test discovery occurs at build time, it is
+  not necessary to re-run CMake when the list of tests changes.
+  However, it requires that :prop_tgt:`CROSSCOMPILING_EMULATOR` is properly set
+  in order to function in a cross-compiling environment.
+
+  Additionally, setting properties on tests is somewhat less convenient, since
+  the tests are not available at CMake time.  Additional test properties may be
+  assigned to the set of tests as a whole using the ``PROPERTIES`` option.  If
+  more fine-grained test control is needed, custom content may be provided
+  through an external CTest script using the :prop_dir:`TEST_INCLUDE_FILES`
+  directory property.  The set of discovered tests is made accessible to such a
+  script via the ``<target>_TESTS`` variable.
+
+  The options are:
+
+  ``target``
+    Specifies the Catch executable, which must be a known CMake executable
+    target.  CMake will substitute the location of the built executable when
+    running the test.
+
+  ``TEST_SPEC arg1...``
+    Specifies test cases, wildcarded test cases, tags and tag expressions to
+    pass to the Catch executable with the ``--list-test-names-only`` argument.
+
+  ``EXTRA_ARGS arg1...``
+    Any extra arguments to pass on the command line to each test case.
+
+  ``WORKING_DIRECTORY dir``
+    Specifies the directory in which to run the discovered test cases.  If this
+    option is not provided, the current binary directory is used.
+
+  ``TEST_PREFIX prefix``
+    Specifies a ``prefix`` to be prepended to the name of each discovered test
+    case.  This can be useful when the same test executable is being used in
+    multiple calls to ``catch_discover_tests()`` but with different
+    ``TEST_SPEC`` or ``EXTRA_ARGS``.
+
+  ``TEST_SUFFIX suffix``
+    Similar to ``TEST_PREFIX`` except the ``suffix`` is appended to the name of
+    every discovered test case.  Both ``TEST_PREFIX`` and ``TEST_SUFFIX`` may
+    be specified.
+
+  ``PROPERTIES name1 value1...``
+    Specifies additional properties to be set on all tests discovered by this
+    invocation of ``catch_discover_tests``.
+
+  ``TEST_LIST var``
+    Make the list of tests available in the variable ``var``, rather than the
+    default ``<target>_TESTS``.  This can be useful when the same test
+    executable is being used in multiple calls to ``catch_discover_tests()``.
+    Note that this variable is only available in CTest.
+
+  ``REPORTER reporter``
+    Use the specified reporter when running the test case. The reporter will
+    be passed to the Catch executable as ``--reporter reporter``.
+
+  ``OUTPUT_DIR dir``
+    If specified, the parameter is passed along as
+    ``--out dir/<test_name>`` to Catch executable. The actual file name is the
+    same as the test name. This should be used instead of
+    ``EXTRA_ARGS --out foo`` to avoid race conditions writing the result output
+    when using parallel test execution.
+
+  ``OUTPUT_PREFIX prefix``
+    May be used in conjunction with ``OUTPUT_DIR``.
+    If specified, ``prefix`` is added to each output file name, like so
+    ``--out dir/prefix<test_name>``.
+
+  ``OUTPUT_SUFFIX suffix``
+    May be used in conjunction with ``OUTPUT_DIR``.
+    If specified, ``suffix`` is added to each output file name, like so
+    ``--out dir/<test_name>suffix``. This can be used to add a file extension to
+    the output e.g. ".xml".
+
+  ``DL_PATHS path...``
+    Specifies paths that need to be set for the dynamic linker to find shared
+    libraries/DLLs when running the test executable (PATH/LD_LIBRARY_PATH respectively).
+    These paths will both be set when retrieving the list of test cases from the
+    test executable and when the tests are executed themselves. This requires
+    cmake/ctest >= 3.22.
+
+#]=======================================================================]
+
+#------------------------------------------------------------------------------
+function(catch_discover_tests TARGET)
+  cmake_parse_arguments(
+    ""
+    ""
+    "TEST_PREFIX;TEST_SUFFIX;WORKING_DIRECTORY;TEST_LIST;REPORTER;OUTPUT_DIR;OUTPUT_PREFIX;OUTPUT_SUFFIX"
+    "TEST_SPEC;EXTRA_ARGS;PROPERTIES;DL_PATHS"
+    ${ARGN}
+  )
+
+  if(NOT _WORKING_DIRECTORY)
+    set(_WORKING_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}")
+  endif()
+  if(NOT _TEST_LIST)
+    set(_TEST_LIST ${TARGET}_TESTS)
+  endif()
+
+  if (_DL_PATHS)
+    if(${CMAKE_VERSION} VERSION_LESS "3.22.0")
+        message(FATAL_ERROR "The DL_PATHS option requires at least cmake 3.22")
+    endif()
+  endif()
+
+  ## Generate a unique name based on the extra arguments
+  string(SHA1 args_hash "${_TEST_SPEC} ${_EXTRA_ARGS} ${_REPORTER} ${_OUTPUT_DIR} ${_OUTPUT_PREFIX} ${_OUTPUT_SUFFIX}")
+  string(SUBSTRING ${args_hash} 0 7 args_hash)
+
+  # Define rule to generate test list for aforementioned test executable
+  set(ctest_include_file "${CMAKE_CURRENT_BINARY_DIR}/${TARGET}_include-${args_hash}.cmake")
+  set(ctest_tests_file "${CMAKE_CURRENT_BINARY_DIR}/${TARGET}_tests-${args_hash}.cmake")
+  get_property(crosscompiling_emulator
+    TARGET ${TARGET}
+    PROPERTY CROSSCOMPILING_EMULATOR
+  )
+  add_custom_command(
+    TARGET ${TARGET} POST_BUILD
+    BYPRODUCTS "${ctest_tests_file}"
+    COMMAND "${CMAKE_COMMAND}"
+            -D "TEST_TARGET=${TARGET}"
+            -D "TEST_EXECUTABLE=$<TARGET_FILE:${TARGET}>"
+            -D "TEST_EXECUTOR=${crosscompiling_emulator}"
+            -D "TEST_WORKING_DIR=${_WORKING_DIRECTORY}"
+            -D "TEST_SPEC=${_TEST_SPEC}"
+            -D "TEST_EXTRA_ARGS=${_EXTRA_ARGS}"
+            -D "TEST_PROPERTIES=${_PROPERTIES}"
+            -D "TEST_PREFIX=${_TEST_PREFIX}"
+            -D "TEST_SUFFIX=${_TEST_SUFFIX}"
+            -D "TEST_LIST=${_TEST_LIST}"
+            -D "TEST_REPORTER=${_REPORTER}"
+            -D "TEST_OUTPUT_DIR=${_OUTPUT_DIR}"
+            -D "TEST_OUTPUT_PREFIX=${_OUTPUT_PREFIX}"
+            -D "TEST_OUTPUT_SUFFIX=${_OUTPUT_SUFFIX}"
+            -D "TEST_DL_PATHS=${_DL_PATHS}"
+            -D "CTEST_FILE=${ctest_tests_file}"
+            -P "${_CATCH_DISCOVER_TESTS_SCRIPT}"
+    VERBATIM
+  )
+
+  file(WRITE "${ctest_include_file}"
+    "if(EXISTS \"${ctest_tests_file}\")\n"
+    "  include(\"${ctest_tests_file}\")\n"
+    "else()\n"
+    "  add_test(${TARGET}_NOT_BUILT-${args_hash} ${TARGET}_NOT_BUILT-${args_hash})\n"
+    "endif()\n"
+  )
+
+  if(NOT ${CMAKE_VERSION} VERSION_LESS "3.10.0") 
+    # Add discovered tests to directory TEST_INCLUDE_FILES
+    set_property(DIRECTORY
+      APPEND PROPERTY TEST_INCLUDE_FILES "${ctest_include_file}"
+    )
+  else()
+    # Add discovered tests as directory TEST_INCLUDE_FILE if possible
+    get_property(test_include_file_set DIRECTORY PROPERTY TEST_INCLUDE_FILE SET)
+    if (NOT ${test_include_file_set})
+      set_property(DIRECTORY
+        PROPERTY TEST_INCLUDE_FILE "${ctest_include_file}"
+      )
+    else()
+      message(FATAL_ERROR
+        "Cannot set more than one TEST_INCLUDE_FILE"
+      )
+    endif()
+  endif()
+
+endfunction()
+
+###############################################################################
+
+set(_CATCH_DISCOVER_TESTS_SCRIPT
+  ${CMAKE_CURRENT_LIST_DIR}/CatchAddTests.cmake
+  CACHE INTERNAL "Catch2 full path to CatchAddTests.cmake helper file"
+)

externals/catch/extras/CatchAddTests.cmake

@@ -0,0 +1,156 @@
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+set(prefix "${TEST_PREFIX}")
+set(suffix "${TEST_SUFFIX}")
+set(spec ${TEST_SPEC})
+set(extra_args ${TEST_EXTRA_ARGS})
+set(properties ${TEST_PROPERTIES})
+set(reporter ${TEST_REPORTER})
+set(output_dir ${TEST_OUTPUT_DIR})
+set(output_prefix ${TEST_OUTPUT_PREFIX})
+set(output_suffix ${TEST_OUTPUT_SUFFIX})
+set(dl_paths ${TEST_DL_PATHS})
+set(script)
+set(suite)
+set(tests)
+
+if(WIN32)
+  set(dl_paths_variable_name PATH)
+elseif(APPLE)
+  set(dl_paths_variable_name DYLD_LIBRARY_PATH)
+else()
+  set(dl_paths_variable_name LD_LIBRARY_PATH)
+endif()
+
+function(add_command NAME)
+  set(_args "")
+  # use ARGV* instead of ARGN, because ARGN splits arrays into multiple arguments
+  math(EXPR _last_arg ${ARGC}-1)
+  foreach(_n RANGE 1 ${_last_arg})
+    set(_arg "${ARGV${_n}}")
+    if(_arg MATCHES "[^-./:a-zA-Z0-9_]")
+      set(_args "${_args} [==[${_arg}]==]") # form a bracket_argument
+    else()
+      set(_args "${_args} ${_arg}")
+    endif()
+  endforeach()
+  set(script "${script}${NAME}(${_args})\n" PARENT_SCOPE)
+endfunction()
+
+# Run test executable to get list of available tests
+if(NOT EXISTS "${TEST_EXECUTABLE}")
+  message(FATAL_ERROR
+    "Specified test executable '${TEST_EXECUTABLE}' does not exist"
+  )
+endif()
+
+if(dl_paths)
+  cmake_path(CONVERT "${dl_paths}" TO_NATIVE_PATH_LIST paths)
+  set(ENV{${dl_paths_variable_name}} "${paths}")
+endif()
+
+execute_process(
+  COMMAND ${TEST_EXECUTOR} "${TEST_EXECUTABLE}" ${spec} --list-tests --verbosity quiet
+  OUTPUT_VARIABLE output
+  RESULT_VARIABLE result
+  WORKING_DIRECTORY "${TEST_WORKING_DIR}"
+)
+if(NOT ${result} EQUAL 0)
+  message(FATAL_ERROR
+    "Error running test executable '${TEST_EXECUTABLE}':\n"
+    "  Result: ${result}\n"
+    "  Output: ${output}\n"
+  )
+endif()
+
+string(REPLACE "\n" ";" output "${output}")
+
+# Run test executable to get list of available reporters
+execute_process(
+  COMMAND ${TEST_EXECUTOR} "${TEST_EXECUTABLE}" ${spec} --list-reporters
+  OUTPUT_VARIABLE reporters_output
+  RESULT_VARIABLE reporters_result
+  WORKING_DIRECTORY "${TEST_WORKING_DIR}"
+)
+if(NOT ${reporters_result} EQUAL 0)
+  message(FATAL_ERROR
+    "Error running test executable '${TEST_EXECUTABLE}':\n"
+    "  Result: ${reporters_result}\n"
+    "  Output: ${reporters_output}\n"
+  )
+endif()
+string(FIND "${reporters_output}" "${reporter}" reporter_is_valid)
+if(reporter AND ${reporter_is_valid} EQUAL -1)
+  message(FATAL_ERROR
+    "\"${reporter}\" is not a valid reporter!\n"
+  )
+endif()
+
+# Prepare reporter
+if(reporter)
+  set(reporter_arg "--reporter ${reporter}")
+endif()
+
+# Prepare output dir
+if(output_dir AND NOT IS_ABSOLUTE ${output_dir})
+  set(output_dir "${TEST_WORKING_DIR}/${output_dir}")
+  if(NOT EXISTS ${output_dir})
+    file(MAKE_DIRECTORY ${output_dir})
+  endif()
+endif()
+
+if(dl_paths)
+  foreach(path ${dl_paths})
+    cmake_path(NATIVE_PATH path native_path)
+    list(APPEND environment_modifications "${dl_paths_variable_name}=path_list_prepend:${native_path}")
+  endforeach()
+endif()
+
+# Parse output
+foreach(line ${output})
+  set(test ${line})
+  # Escape characters in test case names that would be parsed by Catch2
+  set(test_name ${test})
+  foreach(char , [ ])
+    string(REPLACE ${char} "\\${char}" test_name ${test_name})
+  endforeach(char)
+  # ...add output dir
+  if(output_dir)
+    string(REGEX REPLACE "[^A-Za-z0-9_]" "_" test_name_clean ${test_name})
+    set(output_dir_arg "--out ${output_dir}/${output_prefix}${test_name_clean}${output_suffix}")
+  endif()
+  
+  # ...and add to script
+  add_command(add_test
+    "${prefix}${test}${suffix}"
+    ${TEST_EXECUTOR}
+    "${TEST_EXECUTABLE}"
+    "${test_name}"
+    ${extra_args}
+    "${reporter_arg}"
+    "${output_dir_arg}"
+  )
+  add_command(set_tests_properties
+    "${prefix}${test}${suffix}"
+    PROPERTIES
+    WORKING_DIRECTORY "${TEST_WORKING_DIR}"
+    ${properties}
+  )
+
+   if(environment_modifications)
+     add_command(set_tests_properties
+       "${prefix}${test}${suffix}"
+       PROPERTIES
+       ENVIRONMENT_MODIFICATION "${environment_modifications}")
+   endif()
+
+  list(APPEND tests "${prefix}${test}${suffix}")
+endforeach()
+
+# Create a list of all discovered tests, which users may use to e.g. set
+# properties on the tests
+add_command(set ${TEST_LIST} ${tests})
+
+# Write CTest script
+file(WRITE "${CTEST_FILE}" "${script}")

externals/catch/extras/CatchShardTests.cmake

@@ -0,0 +1,66 @@
+
+#              Copyright Catch2 Authors
+# Distributed under the Boost Software License, Version 1.0.
+#   (See accompanying file LICENSE.txt or copy at
+#        https://www.boost.org/LICENSE_1_0.txt)
+
+# SPDX-License-Identifier: BSL-1.0
+
+# Supported optional args:
+#  * SHARD_COUNT - number of shards to split target's tests into
+#  * REPORTER    - reporter spec to use for tests
+#  * TEST_SPEC   - test spec used for filtering tests
+function(catch_add_sharded_tests TARGET)
+  if (${CMAKE_VERSION} VERSION_LESS "3.10.0")
+    message(FATAL_ERROR "add_sharded_catch_tests only supports CMake versions 3.10.0 and up")
+  endif()
+
+  cmake_parse_arguments(
+    ""
+    ""
+    "SHARD_COUNT;REPORTER;TEST_SPEC"
+    ""
+    ${ARGN}
+  )
+  
+  if (NOT DEFINED _SHARD_COUNT)
+    set(_SHARD_COUNT 2)
+  endif()
+
+  # Generate a unique name based on the extra arguments
+  string(SHA1 args_hash "${_TEST_SPEC} ${_EXTRA_ARGS} ${_REPORTER} ${_OUTPUT_DIR} ${_OUTPUT_PREFIX} ${_OUTPUT_SUFFIX} ${_SHARD_COUNT}")
+  string(SUBSTRING ${args_hash} 0 7 args_hash)
+
+  set(ctest_include_file "${CMAKE_CURRENT_BINARY_DIR}/${TARGET}-sharded-tests-include-${args_hash}.cmake")
+  set(ctest_tests_file "${CMAKE_CURRENT_BINARY_DIR}/${TARGET}-sharded-tests-impl-${args_hash}.cmake")
+
+  file(WRITE "${ctest_include_file}"
+    "if(EXISTS \"${ctest_tests_file}\")\n"
+    "  include(\"${ctest_tests_file}\")\n"
+    "else()\n"
+    "  add_test(${TARGET}_NOT_BUILT-${args_hash} ${TARGET}_NOT_BUILT-${args_hash})\n"
+    "endif()\n"
+  )
+
+  set_property(DIRECTORY
+    APPEND PROPERTY TEST_INCLUDE_FILES "${ctest_include_file}"
+  )
+
+  set(shard_impl_script_file "${CMAKE_CURRENT_LIST_DIR}/CatchShardTestsImpl.cmake")
+
+  add_custom_command(
+    TARGET ${TARGET} POST_BUILD
+    BYPRODUCTS "${ctest_tests_file}"
+    COMMAND "${CMAKE_COMMAND}"
+            -D "TARGET_NAME=${TARGET}"
+            -D "TEST_BINARY=$<TARGET_FILE:${TARGET}>"
+            -D "CTEST_FILE=${ctest_tests_file}"
+            -D "SHARD_COUNT=${_SHARD_COUNT}"
+            -D "REPORTER_SPEC=${_REPORTER}"
+            -D "TEST_SPEC=${_TEST_SPEC}"
+            -P "${shard_impl_script_file}"
+    VERBATIM
+  )
+
+
+endfunction()

externals/catch/extras/CatchShardTestsImpl.cmake

@@ -0,0 +1,52 @@
+
+#              Copyright Catch2 Authors
+# Distributed under the Boost Software License, Version 1.0.
+#   (See accompanying file LICENSE.txt or copy at
+#        https://www.boost.org/LICENSE_1_0.txt)
+
+# SPDX-License-Identifier: BSL-1.0
+
+# Indirection for CatchShardTests that allows us to delay the script
+# file generation until build time.
+
+# Expected args:
+#  * TEST_BINARY - full path to the test binary to run sharded
+#  * CTEST_FILE  - full path to ctest script file to write to
+#  * TARGET_NAME - name of the target to shard (used for test names)
+#  * SHARD_COUNT - number of shards to split the binary into
+# Optional args:
+#  * REPORTER_SPEC - reporter specs to be passed down to the binary
+#  * TEST_SPEC     - test spec to pass down to the test binary
+
+if(NOT EXISTS "${TEST_BINARY}")
+  message(FATAL_ERROR
+    "Specified test binary '${TEST_BINARY}' does not exist"
+  )
+endif()
+
+set(other_args "")
+if (TEST_SPEC)
+  set(other_args "${other_args} ${TEST_SPEC}")
+endif()
+if (REPORTER_SPEC)
+  set(other_args "${other_args} --reporter ${REPORTER_SPEC}")
+endif()
+
+# foreach RANGE in cmake is inclusive of the end, so we have to adjust it
+math(EXPR adjusted_shard_count "${SHARD_COUNT} - 1")
+
+file(WRITE "${CTEST_FILE}"
+  "string(RANDOM LENGTH 8 ALPHABET \"0123456789abcdef\" rng_seed)\n"
+  "\n"
+  "foreach(shard_idx RANGE ${adjusted_shard_count})\n"
+  "  add_test(${TARGET_NAME}-shard-" [[${shard_idx}]] "/${adjusted_shard_count}\n"
+  "    ${TEST_BINARY}"
+  " --shard-index " [[${shard_idx}]]
+  " --shard-count ${SHARD_COUNT}"
+  " --rng-seed " [[0x${rng_seed}]]
+  " --order rand"
+  "${other_args}"
+  "\n"
+  "  )\n"
+  "endforeach()\n"
+)

externals/catch/extras/ParseAndAddCatchTests.cmake

@@ -0,0 +1,252 @@
+#==================================================================================================#
+#  supported macros                                                                                #
+#    - TEST_CASE,                                                                                  #
+#    - TEMPLATE_TEST_CASE                                                                          #
+#    - SCENARIO,                                                                                   #
+#    - TEST_CASE_METHOD,                                                                           #
+#    - CATCH_TEST_CASE,                                                                            #
+#    - CATCH_TEMPLATE_TEST_CASE                                                                    #
+#    - CATCH_SCENARIO,                                                                             #
+#    - CATCH_TEST_CASE_METHOD.                                                                     #
+#                                                                                                  #
+#  Usage                                                                                           #
+# 1. make sure this module is in the path or add this otherwise:                                   #
+#    set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake.modules/")              #
+# 2. make sure that you've enabled testing option for the project by the call:                     #
+#    enable_testing()                                                                              #
+# 3. add the lines to the script for testing target (sample CMakeLists.txt):                       #
+#        project(testing_target)                                                                   #
+#        set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake.modules/")          #
+#        enable_testing()                                                                          #
+#                                                                                                  #
+#        find_path(CATCH_INCLUDE_DIR "catch.hpp")                                                  #
+#        include_directories(${INCLUDE_DIRECTORIES} ${CATCH_INCLUDE_DIR})                          #
+#                                                                                                  #
+#        file(GLOB SOURCE_FILES "*.cpp")                                                           #
+#        add_executable(${PROJECT_NAME} ${SOURCE_FILES})                                           #
+#                                                                                                  #
+#        include(ParseAndAddCatchTests)                                                            #
+#        ParseAndAddCatchTests(${PROJECT_NAME})                                                    #
+#                                                                                                  #
+# The following variables affect the behavior of the script:                                       #
+#                                                                                                  #
+#    PARSE_CATCH_TESTS_VERBOSE (Default OFF)                                                       #
+#    -- enables debug messages                                                                     #
+#    PARSE_CATCH_TESTS_NO_HIDDEN_TESTS (Default OFF)                                               #
+#    -- excludes tests marked with [!hide], [.] or [.foo] tags                                     #
+#    PARSE_CATCH_TESTS_ADD_FIXTURE_IN_TEST_NAME (Default ON)                                       #
+#    -- adds fixture class name to the test name                                                   #
+#    PARSE_CATCH_TESTS_ADD_TARGET_IN_TEST_NAME (Default ON)                                        #
+#    -- adds cmake target name to the test name                                                    #
+#    PARSE_CATCH_TESTS_ADD_TO_CONFIGURE_DEPENDS (Default OFF)                                      #
+#    -- causes CMake to rerun when file with tests changes so that new tests will be discovered    #
+#                                                                                                  #
+# One can also set (locally) the optional variable OptionalCatchTestLauncher to precise the way    #
+# a test should be run. For instance to use test MPI, one can write                                #
+#     set(OptionalCatchTestLauncher ${MPIEXEC} ${MPIEXEC_NUMPROC_FLAG} ${NUMPROC})                 #
+# just before calling this ParseAndAddCatchTests function                                          #
+#                                                                                                  #
+# The AdditionalCatchParameters optional variable can be used to pass extra argument to the test   #
+# command. For example, to include successful tests in the output, one can write                   #
+#     set(AdditionalCatchParameters --success)                                                     #
+#                                                                                                  #
+# After the script, the ParseAndAddCatchTests_TESTS property for the target, and for each source   #
+# file in the target is set, and contains the list of the tests extracted from that target, or     #
+# from that file. This is useful, for example to add further labels or properties to the tests.    #
+#                                                                                                  #
+#==================================================================================================#
+
+if (CMAKE_MINIMUM_REQUIRED_VERSION VERSION_LESS 2.8.8)
+  message(FATAL_ERROR "ParseAndAddCatchTests requires CMake 2.8.8 or newer")
+endif()
+
+option(PARSE_CATCH_TESTS_VERBOSE "Print Catch to CTest parser debug messages" OFF)
+option(PARSE_CATCH_TESTS_NO_HIDDEN_TESTS "Exclude tests with [!hide], [.] or [.foo] tags" OFF)
+option(PARSE_CATCH_TESTS_ADD_FIXTURE_IN_TEST_NAME "Add fixture class name to the test name" ON)
+option(PARSE_CATCH_TESTS_ADD_TARGET_IN_TEST_NAME "Add target name to the test name" ON)
+option(PARSE_CATCH_TESTS_ADD_TO_CONFIGURE_DEPENDS "Add test file to CMAKE_CONFIGURE_DEPENDS property" OFF)
+
+function(ParseAndAddCatchTests_PrintDebugMessage)
+    if(PARSE_CATCH_TESTS_VERBOSE)
+            message(STATUS "ParseAndAddCatchTests: ${ARGV}")
+    endif()
+endfunction()
+
+# This removes the contents between
+#  - block comments (i.e. /* ... */)
+#  - full line comments (i.e. // ... )
+# contents have been read into '${CppCode}'.
+# !keep partial line comments
+function(ParseAndAddCatchTests_RemoveComments CppCode)
+  string(ASCII 2 CMakeBeginBlockComment)
+  string(ASCII 3 CMakeEndBlockComment)
+  string(REGEX REPLACE "/\\*" "${CMakeBeginBlockComment}" ${CppCode} "${${CppCode}}")
+  string(REGEX REPLACE "\\*/" "${CMakeEndBlockComment}" ${CppCode} "${${CppCode}}")
+  string(REGEX REPLACE "${CMakeBeginBlockComment}[^${CMakeEndBlockComment}]*${CMakeEndBlockComment}" "" ${CppCode} "${${CppCode}}")
+  string(REGEX REPLACE "\n[ \t]*//+[^\n]+" "\n" ${CppCode} "${${CppCode}}")
+
+  set(${CppCode} "${${CppCode}}" PARENT_SCOPE)
+endfunction()
+
+# Worker function
+function(ParseAndAddCatchTests_ParseFile SourceFile TestTarget)
+    # If SourceFile is an object library, do not scan it (as it is not a file). Exit without giving a warning about a missing file.
+    if(SourceFile MATCHES "\\\$<TARGET_OBJECTS:.+>")
+        ParseAndAddCatchTests_PrintDebugMessage("Detected OBJECT library: ${SourceFile} this will not be scanned for tests.")
+        return()
+    endif()
+    # According to CMake docs EXISTS behavior is well-defined only for full paths.
+    get_filename_component(SourceFile ${SourceFile} ABSOLUTE)
+    if(NOT EXISTS ${SourceFile})
+        message(WARNING "Cannot find source file: ${SourceFile}")
+        return()
+    endif()
+    ParseAndAddCatchTests_PrintDebugMessage("parsing ${SourceFile}")
+    file(STRINGS ${SourceFile} Contents NEWLINE_CONSUME)
+
+    # Remove block and fullline comments
+    ParseAndAddCatchTests_RemoveComments(Contents)
+
+    # Find definition of test names
+    # https://regex101.com/r/JygOND/1
+    string(REGEX MATCHALL "[ \t]*(CATCH_)?(TEMPLATE_)?(TEST_CASE_METHOD|SCENARIO|TEST_CASE)[ \t]*\\([ \t\n]*\"[^\"]*\"[ \t\n]*(,[ \t\n]*\"[^\"]*\")?(,[ \t\n]*[^\,\)]*)*\\)[ \t\n]*\{+[ \t]*(//[^\n]*[Tt][Ii][Mm][Ee][Oo][Uu][Tt][ \t]*[0-9]+)*" Tests "${Contents}")
+
+    if(PARSE_CATCH_TESTS_ADD_TO_CONFIGURE_DEPENDS AND Tests)
+      ParseAndAddCatchTests_PrintDebugMessage("Adding ${SourceFile} to CMAKE_CONFIGURE_DEPENDS property")
+      set_property(
+        DIRECTORY
+        APPEND
+        PROPERTY CMAKE_CONFIGURE_DEPENDS ${SourceFile}
+      )
+    endif()
+
+    # check CMP0110 policy for new add_test() behavior
+    if(POLICY CMP0110)
+        cmake_policy(GET CMP0110 _cmp0110_value) # new add_test() behavior
+    else()
+        # just to be thorough explicitly set the variable
+        set(_cmp0110_value)
+    endif()
+
+    foreach(TestName ${Tests})
+        # Strip newlines
+        string(REGEX REPLACE "\\\\\n|\n" "" TestName "${TestName}")
+
+        # Get test type and fixture if applicable
+        string(REGEX MATCH "(CATCH_)?(TEMPLATE_)?(TEST_CASE_METHOD|SCENARIO|TEST_CASE)[ \t]*\\([^,^\"]*" TestTypeAndFixture "${TestName}")
+        string(REGEX MATCH "(CATCH_)?(TEMPLATE_)?(TEST_CASE_METHOD|SCENARIO|TEST_CASE)" TestType "${TestTypeAndFixture}")
+        string(REGEX REPLACE "${TestType}\\([ \t]*" "" TestFixture "${TestTypeAndFixture}")
+
+        # Get string parts of test definition
+        string(REGEX MATCHALL "\"+([^\\^\"]|\\\\\")+\"+" TestStrings "${TestName}")
+
+        # Strip wrapping quotation marks
+        string(REGEX REPLACE "^\"(.*)\"$" "\\1" TestStrings "${TestStrings}")
+        string(REPLACE "\";\"" ";" TestStrings "${TestStrings}")
+
+        # Validate that a test name and tags have been provided
+        list(LENGTH TestStrings TestStringsLength)
+        if(TestStringsLength GREATER 2 OR TestStringsLength LESS 1)
+            message(FATAL_ERROR "You must provide a valid test name and tags for all tests in ${SourceFile}")
+        endif()
+
+        # Assign name and tags
+        list(GET TestStrings 0 Name)
+        if("${TestType}" STREQUAL "SCENARIO")
+            set(Name "Scenario: ${Name}")
+        endif()
+        if(PARSE_CATCH_TESTS_ADD_FIXTURE_IN_TEST_NAME AND "${TestType}" MATCHES "(CATCH_)?TEST_CASE_METHOD" AND TestFixture )
+            set(CTestName "${TestFixture}:${Name}")
+        else()
+            set(CTestName "${Name}")
+        endif()
+        if(PARSE_CATCH_TESTS_ADD_TARGET_IN_TEST_NAME)
+            set(CTestName "${TestTarget}:${CTestName}")
+        endif()
+        # add target to labels to enable running all tests added from this target
+        set(Labels ${TestTarget})
+        if(TestStringsLength EQUAL 2)
+            list(GET TestStrings 1 Tags)
+            string(TOLOWER "${Tags}" Tags)
+            # remove target from labels if the test is hidden
+            if("${Tags}" MATCHES ".*\\[!?(hide|\\.)\\].*")
+                list(REMOVE_ITEM Labels ${TestTarget})
+            endif()
+            string(REPLACE "]" ";" Tags "${Tags}")
+            string(REPLACE "[" "" Tags "${Tags}")
+        else()
+          # unset tags variable from previous loop
+          unset(Tags)
+        endif()
+
+        list(APPEND Labels ${Tags})
+
+        set(HiddenTagFound OFF)
+        foreach(label ${Labels})
+            string(REGEX MATCH "^!hide|^\\." result ${label})
+            if(result)
+                set(HiddenTagFound ON)
+                break()
+            endif(result)
+        endforeach(label)
+        if(PARSE_CATCH_TESTS_NO_HIDDEN_TESTS AND ${HiddenTagFound} AND ${CMAKE_VERSION} VERSION_LESS "3.9")
+            ParseAndAddCatchTests_PrintDebugMessage("Skipping test \"${CTestName}\" as it has [!hide], [.] or [.foo] label")
+        else()
+            ParseAndAddCatchTests_PrintDebugMessage("Adding test \"${CTestName}\"")
+            if(Labels)
+                ParseAndAddCatchTests_PrintDebugMessage("Setting labels to ${Labels}")
+            endif()
+
+            # Escape commas in the test spec
+            string(REPLACE "," "\\," Name ${Name})
+
+            # Work around CMake 3.18.0 change in `add_test()`, before the escaped quotes were necessary,
+            # only with CMake 3.18.0 the escaped double quotes confuse the call. This change is reverted in 3.18.1
+            # And properly introduced in 3.19 with the CMP0110 policy
+            if(_cmp0110_value STREQUAL "NEW" OR ${CMAKE_VERSION} VERSION_EQUAL "3.18")
+                ParseAndAddCatchTests_PrintDebugMessage("CMP0110 set to NEW, no need for add_test(\"\") workaround")
+            else()
+                ParseAndAddCatchTests_PrintDebugMessage("CMP0110 set to OLD adding \"\" for add_test() workaround")
+                set(CTestName "\"${CTestName}\"")
+            endif()
+
+            # Handle template test cases
+            if("${TestTypeAndFixture}" MATCHES ".*TEMPLATE_.*")
+              set(Name "${Name} - *")
+            endif()
+
+            # Add the test and set its properties
+            add_test(NAME "${CTestName}" COMMAND ${OptionalCatchTestLauncher} $<TARGET_FILE:${TestTarget}> ${Name} ${AdditionalCatchParameters})
+            # Old CMake versions do not document VERSION_GREATER_EQUAL, so we use VERSION_GREATER with 3.8 instead
+            if(PARSE_CATCH_TESTS_NO_HIDDEN_TESTS AND ${HiddenTagFound} AND ${CMAKE_VERSION} VERSION_GREATER "3.8")
+                ParseAndAddCatchTests_PrintDebugMessage("Setting DISABLED test property")
+                set_tests_properties("${CTestName}" PROPERTIES DISABLED ON)
+            else()
+                set_tests_properties("${CTestName}" PROPERTIES FAIL_REGULAR_EXPRESSION "No tests ran"
+                                                        LABELS "${Labels}")
+            endif()
+            set_property(
+              TARGET ${TestTarget}
+              APPEND
+              PROPERTY ParseAndAddCatchTests_TESTS "${CTestName}")
+            set_property(
+              SOURCE ${SourceFile}
+              APPEND
+              PROPERTY ParseAndAddCatchTests_TESTS "${CTestName}")
+        endif()
+
+
+    endforeach()
+endfunction()
+
+# entry point
+function(ParseAndAddCatchTests TestTarget)
+    message(DEPRECATION "ParseAndAddCatchTest: function deprecated because of possibility of missed test cases. Consider using 'catch_discover_tests' from 'Catch.cmake'")
+    ParseAndAddCatchTests_PrintDebugMessage("Started parsing ${TestTarget}")
+    get_target_property(SourceFiles ${TestTarget} SOURCES)
+    ParseAndAddCatchTests_PrintDebugMessage("Found the following sources: ${SourceFiles}")
+    foreach(SourceFile ${SourceFiles})
+        ParseAndAddCatchTests_ParseFile(${SourceFile} ${TestTarget})
+    endforeach()
+    ParseAndAddCatchTests_PrintDebugMessage("Finished parsing ${TestTarget}")
+endfunction()

externals/catch/extras/gdbinit

@@ -0,0 +1,16 @@
+#
+# This file provides a way to skip stepping into Catch code when debugging with gdb.
+#
+# With the gdb "skip" command you can tell gdb to skip files or functions during debugging.
+# see https://xaizek.github.io/2016-05-26/skipping-standard-library-in-gdb/ for an example
+#
+# Basically the following line tells gdb to skip all functions containing the
+# regexp "Catch", which matches the complete Catch namespace.
+# If you want to skip just some parts of the Catch code you can modify the
+# regexp accordingly.
+# 
+# If you want to permanently skip stepping into Catch code copy the following
+# line into your ~/.gdbinit file
+# 
+
+skip -rfu Catch

externals/catch/extras/lldbinit

@@ -0,0 +1,16 @@
+#
+# This file provides a way to skip stepping into Catch code when debugging with lldb.
+#
+# With the setting "target.process.thread.step-avoid-regexp" you can tell lldb
+# to skip functions matching the regexp
+#
+# Basically the following line tells lldb to skip all functions containing the
+# regexp "Catch", which matches the complete Catch namespace.
+# If you want to skip just some parts of the Catch code you can modify the
+# regexp accordingly.
+#
+# If you want to permanently skip stepping into Catch code copy the following
+# line into your ~/.lldbinit file
+#
+
+settings set target.process.thread.step-avoid-regexp Catch

externals/catch/fuzzing/CMakeLists.txt

@@ -0,0 +1,20 @@
+# License: Boost 1.0
+# By Paul Dreik 2020
+
+# add a library that brings in the main() function from libfuzzer
+# and has all the dependencies, so the individual fuzzers can be
+# added one line each.
+add_library(fuzzhelper NullOStream.h NullOStream.cpp)
+target_link_libraries(fuzzhelper PUBLIC Catch2::Catch2)
+
+# use C++17 so we can get string_view
+target_compile_features(fuzzhelper PUBLIC cxx_std_17)
+
+# This should be possible to set from the outside to be oss-fuzz compatible,
+# fix later. For now, target libFuzzer only.
+target_link_options(fuzzhelper PUBLIC "-fsanitize=fuzzer")
+
+foreach(fuzzer TestSpecParser XmlWriter textflow)
+add_executable(fuzz_${fuzzer} fuzz_${fuzzer}.cpp)
+target_link_libraries(fuzz_${fuzzer} PRIVATE fuzzhelper)
+endforeach()