def test_withoutFailureResult(self):
        """
        L{SynchronousTestCase.failureResultOf} raises
        L{SynchronousTestCase.failureException} when called with a L{Deferred}
        with no current result.
        """
        self.assertRaises(
            self.failureException, self.failureResultOf, Deferred())

        L{SynchronousTestCase.failureResultOf} raises
        L{SynchronousTestCase.failureException} when called with a L{Deferred}
        with no current result.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_assertions.py