def test_file_for_file_module_when_None(self):
        """No error when ``module.__file__`` is :py:data:`None`."""

        class test_module:
            __file__ = None

        assert plugins.Autoreloader._file_for_file_module(test_module) is None
No error when ``module.__file__`` is :py:data:`None`.
cherrypy/test/test_plugins.py