Unit tests

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Unit tests

Meson comes with a fully functional unit test system. To use it simply build an executable and then use it in a test.

e = executable('prog', 'testprog.c')
test('name of test', e)

You can add as many tests as you want. They are run with the command ninja test.

Meson captures the output of all tests and writes it in the log file meson-logs/testlog.txt.

Test parameters

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 flags --enable-gcov, 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 the output of these commands is written to the log directory meson-logs in your build directory.

Valgrind

If you have Valgrind installed, Meson will provide a test-valgrind target, which runs all your unit tests under Valgrind. The full Valgrind log can be found in meson-logs/testlog-valgrind.txt

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 dbus 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

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