def test_failsWithEmptyFilename(self):
        """
        An empty filename raises an error.
        """
        self.assertRaises(ValueError, strcred.makeChecker, 'file')
        self.assertRaises(ValueError, strcred.makeChecker, 'file:')

        An empty filename raises an error.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/cred/test/test_strcred.py