def test_invalid_token_raises_exception(self):
interpreter = Interpreter('')
interpreter.current_token = Token(PLUS, '+')
with self.assertRaises(InvalidTokenException) as exc:
interpreter.eat([DIVIDE, MULTIPLY])
def test_valid_token_calls_get_next_token(self):
interpreter = Interpreter('')
with patch.object(interpreter, 'get_next_token') as get_next_token:
interpreter.current_token = Token(PLUS, '+')
interpreter.eat([PLUS, SUBTRACT, DIVIDE, MULTIPLY])
self.assertTrue(get_next_token.called)