def test_noTodoProvided(self):
        """
        If no C{Todo} is provided to C{addExpectedFailure}, then
        L{reporter.Reporter} makes up a sensible default.

        This allows standard Python unittests to use Twisted reporters.
        """
        failure = Failure(Exception())
        self.result.addExpectedFailure(self.test, failure)
        [(test, error, todo)] = self._getTodos(self.result)
        self.assertEqual(test, self.test)
        self.assertEqual(error, failure)
        self.assertEqual(repr(todo), repr(makeTodo('Test expected to fail')))

        If no C{Todo} is provided to C{addExpectedFailure}, then
        L{reporter.Reporter} makes up a sensible default.

        This allows standard Python unittests to use Twisted reporters.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_reporter.py