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| short-description |
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| Meson's own unit-test system |
Some tests require the use of command line arguments or environment variables. These are simple to define.
test('command line test', exe, args : ['first', 'second'])
test('envvar test', exe2, env : ['key1=value1', 'key2=value2'])
Note how you need to specify multiple values as an array.
Coverage
If you enable coverage measurements by giving Meson the command line flag -Db_coverage=true, you can generate coverage reports. Meson will autodetect what coverage generator tools you have installed and will generate the corresponding targets. These targets are coverage-xml and coverage-text which are both provided by Gcovr and coverage-html, which requires Lcov and GenHTML.
The output of these commands is written to the log directory meson-logs in your build directory.
Parallelism
To reduce test times, Meson will by default run multiple unit tests in parallel. It is common to have some tests which can not be run in parallel because they require unique hold on some resource such as a file or a D-Bus name. You have to specify these tests with a keyword argument.
test('unique test', t, is_parallel : false)
Meson will then make sure that no other unit test is running at the same time. Non-parallel tests take longer to run so it is recommended that you write your unit tests to be parallel executable whenever possible.
By default Meson uses as many concurrent processes as there are cores on the test machine. You can override this with the environment variable MESON_TESTTHREADS like this.
$ MESON_TESTTHREADS=5 ninja test
Skipped tests
Sometimes a test can only determine at runtime that it can not be run. The GNU standard approach in this case is to exit the program with error code 77. Meson will detect this and report these tests as skipped rather than failed. This behavior was added in version 0.37.0.
Testing tool
In version 0.37.0 a new tool called mesontest was added. The goal of this tool is to provide a simple way to run tests in a variety of different ways. The tool is designed to be run in the build directory.
The simplest thing to do is just to run all tests, which is equivalent to running ninja test.
$ mesontest
You can also run only a single test by giving its name:
$ mesontest testname
Sometimes you need to run the tests multiple times, which is done like this:
$ mesontest --repeat=10
Invoking tests via a helper executable such as Valgrind can be done with the --wrap argument
$ mesontest --wrap=valgrind testname
Arguments to the wrapper binary can be given like this:
$ mesontest --wrap='valgrind --tool=helgrind' testname
Meson also supports running the tests under GDB. Just doing this:
$ mesontest --gdb testname
Mesontest will launch gdb all set up to run the test. Just type run in the GDB command prompt to start the program.
The second use case is a test that segfaults only rarely. In this case you can invoke the following command:
$ mesontest --gdb --repeat=10000 testname
This runs the test up to 10 000 times under GDB automatically. If the program crashes, GDB will halt and the user can debug the application. Note that testing timeouts are disabled in this case so mesontest will not kill gdb while the developer is still debugging it. The downside is that if the test binary freezes, the test runner will wait forever.
For further information see the command line help of Mesontest by running mesontest -h.