[Pytest-commit] Issue #749: multiprocessing broken since 2.7.1 on Windows (pytest-dev/pytest)

[Marc Schlaich]

New issue 749: multiprocessing broken since 2.7.1 on Windows
https://bitbucket.org/pytest-dev/pytest/issue/749/multiprocessing-broken-since-271-on

Marc Schlaich:

With pytest 2.7.1, Processes with multiprocessing don't start anymore, I'm seeing this in stdout:

    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "c:\python27\Lib\multiprocessing\forking.py", line 380, in main
        prepare(preparation_data)
      File "c:\python27\Lib\multiprocessing\forking.py", line 488, in prepare
        assert main_name not in sys.modules, main_name
    AssertionError: __main__

This is probably due to this upstream issue with wheels: https://github.com/pypa/pip/issues/1891

Installing pytest not as wheel with `pip install --no-use-wheel` resolves this issue.