CODEWITHSUNDEEP
pythonpytest-xdist
Kilian Foth
Kilian Foth

Reputation: 14376

Can I get pytest-xdist to parallelize test *files* and not test *methods*?

I have a large test suite that contains thousands of tests of an information extraction engine. There are about five hundred inputs, and I have to extract 10-90 items of information from each input.

For maximal transparency, I test each item from each input separately, so that I can look at the pytest log and tell exactly which tests flip after a code change. But since it's inefficient to run extraction within each test dozens of times, I organized my tests so that the extraction is done only once for each input, a test-global variable is set and then each test simply checks one aspect of the result.

It seems that this set-up prevents any speedup gains when using python-xdist. Apparently, pytest will still initialize all 500 test files in one thread and then have individual workers execute the test methods - but the actual tests take no time, so I save nothing!

Is there a simple way to instruct pytest-xdist to distribute the test files rather than the test methods to the workers, so that I can parallelize the 500 calls to the engine?

Upvotes: 3

Views: 3705

Answers (1)

toolateitsme
toolateitsme

Reputation: 64

According to official docs - https://pytest-xdist.readthedocs.io/en/latest/distribution.html, you can use one of the following:

  • custom groups (mark all related tests with @pytest.mark.xdist_group), and run cli with flag --dist loadgroup. It can help you run entire groups (in your cases - all methods of class) in isolated worker
  • if you use OOP style (Test classes with test methods or modules with tests) - use pytest CLI flag --dist loadscope , this approach will make groups automatically (modules, or classes) and guarantees that all tests in a group run in the same process.

Upvotes: 3

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