def test_orderConflictWithRandom(self):
        """
        C{parseOptions} raises a C{UsageError} when C{--order} is passed along
        with C{--random}.
        """
        error = self.assertRaises(
            UsageError,
            self.options.parseOptions,
            ["--order", "alphabetical", "--random", "1234"])
        self.assertEqual("You can't specify --random when using --order",
                         str(error))

        C{parseOptions} raises a C{UsageError} when C{--order} is passed along
        with C{--random}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_script.py