PytestWarning: Module already imported so cannot be rewritten: pytest_remotedata

I created some unit tests and run them from the same file. For tests in the same file:

if __name__ == "__main__":
    import pytest
    pytest.main(['--tb=short', __file__])

For tests in another file:

if __name__ == '__main__':
    import pytest
    pytest.main(['./test_stuff.py', "--capture=sys"])

In either case, when I execute the file the first time, it works fine, but the second and subsequent times it gives a bunch of warnings:

============================== warnings summary ===============================
C:\Anaconda3\lib\site-packages\_pytest\config\__init__.py:754
  C:\Anaconda3\lib\site-packages\_pytest\config\__init__.py:754: PytestWarning: Module already imported so cannot be rewritten: pytest_remotedata
    self._mark_plugins_for_rewrite(hook)
  C:\Anaconda3\lib\site-packages\_pytest\config\__init__.py:754: PytestWarning: Module already imported so cannot be rewritten: pytest_openfiles
    self._mark_plugins_for_rewrite(hook)
  C:\Anaconda3\lib\site-packages\_pytest\config\__init__.py:754: PytestWarning: Module already imported so cannot be rewritten: pytest_doctestplus
    self._mark_plugins_for_rewrite(hook)
  C:\Anaconda3\lib\site-packages\_pytest\config\__init__.py:754: PytestWarning: Module already imported so cannot be rewritten: pytest_arraydiff
    self._mark_plugins_for_rewrite(hook)

-- Docs: https://docs.pytest.org/en/latest/warnings.html
==================== 1 passed, 4 warnings in 0.06 seconds 

Is there any way to make these warnings go away?

Restarting the kernel works, but IPython's %reset and %clear aren't enough to fix it, either.

Use subprocess instead of pytest.main:

if __name__ == "__main__":
    import subprocess
    subprocess.call(['pytest', '--tb=short', str(__file__)])

If the above does not print anything, try the workaround (as suggested in comments):

if __name__ == "__main__":
    from subprocess import Popen, PIPE
    with Popen(['pytest',
                '--tb=short',  # shorter traceback format
                str(__file__)], stdout=PIPE, bufsize=1,
                universal_newlines=True) as p:
        for line in p.stdout:
            print(line, end='')