v811_spc009/external/catch2/docs/cmake-integration.md

CMake integration

Contents
CMake target
Automatic test registration
CMake project options
Installing Catch2 from git repository

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_CASEs in CTest

CMake target

Catch2's CMake build exports an interface target Catch2::Catch2. Linking against it will add the proper include path and all necessary capabilities to the resulting binary.

This means that if Catch2 has been installed on the system, it should be enough to do:

find_package(Catch2 REQUIRED)
target_link_libraries(tests Catch2::Catch2)

This target is also provided when Catch2 is used as a subdirectory. Assuming that Catch2 has been cloned to lib/Catch2:

add_subdirectory(lib/Catch2)
target_link_libraries(tests Catch2::Catch2)

Automatic test registration

Catch2's repository also contains two CMake scripts that help users with automatically registering their TEST_CASEs with CTest. They can be found in the contrib folder, and are

1. Catch.cmake (and its dependency CatchAddTests.cmake)
2. ParseAndAddCatchTests.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.

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_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 Catch2::Catch2)

include(CTest)
include(Catch)
catch_discover_tests(foo)

Customization

catch_discover_tests can be given several extra argumets:

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]
)

• 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.

ParseAndAddCatchTests.cmake

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.

Usage

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 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 any of [!hide], [.] 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

set(OptionalCatchTestLauncher ${MPIEXEC} ${MPIEXEC_NUMPROC_FLAG} ${NUMPROC})
ParseAndAddCatchTests(mpi_foo)
unset(OptionalCatchTestLauncher)
ParseAndAddCatchTests(bar)

CMake project options

Catch2's CMake project also provides some options for other projects that consume it. These are

• 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_INSTALL_DOCS -- When ON, Catch2's documentation will be included in the installation. Defaults to ON.
• CATCH_INSTALL_HELPERS -- When ON, Catch2's contrib folder will be included in the installation. Defaults to ON.
• BUILD_TESTING -- When ON and the project is not used as a subproject, Catch2's test binary will be built. Defaults to ON.

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 when configuring the build, and then modify your calls to find_package accordingly.

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