pytest-xdist
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pytest-dev
pytest does not run tests in parallel and hangs after running first test
I'm facing a very weird issue. When I try to run my test in parallel- Only 1 browser opens even when I execute pytest -n 2 After first test is successful, pytest just hangs and it does not even timeout Has anyone faced this issue?
py.test -vv -n 2 =================================================================================================== test session starts =================================================================================================== platform darwin -- Python 3.7.3, pytest-5.4.1, py-1.10.0, pluggy-0.13.1 -- ///* cachedir: .pytest_cache rootdir: //, inifile: pytest.ini plugins: xdist-1.31.0, allure-pytest-2.8.40, repeat-0.9.1, forked-1.1.3, timeout-1.4.2 [gw0] darwin Python 3.7.3 cwd: // [gw1] darwin Python 3.7.3 cwd: /**/* collected 8 items [gw0] Python 3.7.3 (default, Apr 24 2020, 18:51:23) -- [Clang 11.0.3 (clang-1103.0.32.62)] [gw1] Python 3.7.3 (default, Apr 24 2020, 18:51:23) -- [Clang 11.0.3 (clang-1103.0.32.62)] gw0 [8] / gw1 [8] scheduling tests via MarkBasedScheduler
test1 [gw1] [ 12%] PASSED test1
It will get stuck after this.
I get the same issue sometimes, it happens randomly and it's quite hard to reproduce. Would it be related to multiprocessing issues using the fork sys call? https://bugs.python.org/issue40399 https://docs.python.org/3/library/multiprocessing.html#multiprocessing.set_start_method
My tests are multi-threaded and all sorts of weird hangs happen. Does pytests-xdist use fork system call when making tests parallel?
My setup is on linux (Ubuntu 20.04)
Pytest xdist starts a new non forked python, however execnet has a broken treading startup, so pytest control may not end up in the main thread in the worker
A fix is in very early planning, but may take a few months to delivery
