Dealing with `atexit` and setup.py test command deleting modules.

atexit_setup.py

from setuptools import setup
from setuptools.command.test import test as TestCommand

class PyTest(TestCommand):
    def finalize_options(self):
        TestCommand.finalize_options(self)
        self.test_args = []
        self.test_suite = True

    def run_tests(self):
        import pytest
        import sys

        errno = pytest.main(self.test_args)
        self.handle_exit()
        sys.exit(errno)

    @staticmethod
    def handle_exit():
        import atexit

        atexit._run_exitfuncs()

setup(cmdclass={'test': PyTest})