Hangs after pytest tests complete

[ikamensh]

Hi,

I am using Pathos to do multiprocessing with objects containing lambda functions. When I run my tests, Pathos doesn't return although tests complete successfully:

(go-ast-go-EjGnZ3Kb-py3.8) ~/P/project (master|●3✚1…) $ pytest .                                                                                                           13:31:38
=============================================================================== test session starts ================================================================================
platform darwin -- Python 3.8.1+, pytest-5.3.5, py-1.8.1, pluggy-0.13.1
rootdir: /Users/username/PycharmProjects/project
plugins: timeout-1.3.4
collected 14 items                                                                                                                                                                 

tests/test_compare.py .                                                                                                                                                      [  7%]
tests/test_continuous.py ...                                                                                                                                                 [ 28%]
tests/test_problem.py .                                                                                                                                                      [ 35%]
tests/test_solution.py .                                                                                                                                                     [ 42%]
tests/test_solver.py ..                                                                                                                                                      [ 57%]
tests/test_tsp.py ......                                                                                                                                                     [100%]

================================================================================ 14 passed in 0.54s ================================================================================
^[[A


^CError in atexit._run_exitfuncs:
Traceback (most recent call last):
  File "/lib/python3.8/site-packages/multiprocess/util.py", line 277, in _run_finalizers
    finalizer()
  File "/lib/python3.8/site-packages/multiprocess/util.py", line 201, in __call__
    res = self._callback(*self._args, **self._kwargs)
  File "/lib/python3.8/site-packages/multiprocess/pool.py", line 689, in _terminate_pool
    cls._help_stuff_finish(inqueue, task_handler, len(pool))
  File "/lib/python3.8/site-packages/multiprocess/pool.py", line 674, in _help_stuff_finish
    inqueue._rlock.acquire()
KeyboardInterrupt

Similar problem occured when I had some faulty code and it raised exception in one of the subprocesses - the whole program didn't terminate, and hanged until given a KeyboardInterrupt.

OS: macOS 10.14.6

[mmckerns]

I think pytest doesn't play well with mutiprocessing (and hence pathos). Specifically I've been rolling my own tests in test.__main__ and not using pytest since reading the pytest docs a way back, and seeing notes about issues with multiprocessing.

I am on the fence about putting pytest support in "won't-fix", so I'll leave this open for now.