gh-109817: Do not copy all test cases into the worker process - #155713
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serhiy-storchaka merged 1 commit intoAug 13, 2026
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With --single-process-per-case, tests and case_groups contain all test cases of the whole run. Copying them for every test case was slow and could produce a too long command line. The worker needs neither.
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Aug 14, 2026
…ythonGH-155713) With --single-process-per-case, tests and case_groups contain all test cases of the whole run. Copying them for every test case was slow and could produce a too long command line. The worker needs neither.
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With
--single-process-per-case,testsandcase_groupscontain all test cases of the whole run.create_worker_runtests()copies them for every test case and serializes them as a single command line argument../python -m test --single-process-per-case test_asynciofailed withOSError: [Errno 7] Argument list too long. The copying is also slow and holds the GIL: with-j32, the number of test cases executed in 75 seconds increased from 1066 to 3214.The worker runs the tests it is given, so it needs neither.