def test_LISTWithBadArgument(self):
        """
        Test that non-integers and out-of-bound integers produce appropriate
        error responses.
        """
        p = self.pop3Server
        s = self.pop3Transport

        p.lineReceived(b"LIST a")
        self.assertEqual(
            s.getvalue(),
            b"-ERR Invalid message-number: a\r\n")
        s.seek(0)
        s.truncate(0)

        p.lineReceived(b"LIST 0")
        self.assertEqual(
            s.getvalue(),
            b"-ERR Invalid message-number: 0\r\n")
        s.seek(0)
        s.truncate(0)

        p.lineReceived(b"LIST 2")
        self.assertEqual(
            s.getvalue(),
            b"-ERR Invalid message-number: 2\r\n")
        s.seek(0)
        s.truncate(0)

        Test that non-integers and out-of-bound integers produce appropriate
        error responses.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/test/test_pop3.py