def test_noOutputForInput(self):
        """
        L{Automaton.outputForInput} raises L{NoTransition} if no
        transition for that input is defined.
        """
        a = Automaton()
        self.assertRaises(NoTransition, a.outputForInput,
                          "no-state", "no-symbol")

        L{Automaton.outputForInput} raises L{NoTransition} if no
        transition for that input is defined.
        
stackoverflow/venv/lib/python3.6/site-packages/automat/_test/test_core.py