def test_emptyChild(self):
        """
        The C{''} child of a L{File} which corresponds to a directory in the
        filesystem is a L{DirectoryLister}.
        """
        base = FilePath(self.mktemp())
        base.makedirs()
        file = static.File(base.path)

        request = DummyRequest([b''])
        child = resource.getChildForRequest(file, request)
        self.assertIsInstance(child, static.DirectoryLister)
        self.assertEqual(child.path, base.path)

        The C{''} child of a L{File} which corresponds to a directory in the
        filesystem is a L{DirectoryLister}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_static.py