def testPToN(self):
        """
        L{twisted.python.compat.inet_pton} parses IPv4 and IPv6 addresses in a
        manner similar to that of L{socket.inet_pton}.
        """
        from twisted.python.compat import inet_pton

        f = lambda a: inet_pton(socket.AF_INET6, a)
        g = lambda a: inet_pton(socket.AF_INET, a)

        self.assertEqual('\x00\x00\x00\x00', g('0.0.0.0'))
        self.assertEqual('\xff\x00\xff\x00', g('255.0.255.0'))
        self.assertEqual('\xaa\xaa\xaa\xaa', g('170.170.170.170'))

        self.assertEqual('\x00' * 16, f('::'))
        self.assertEqual('\x00' * 16, f('0::0'))
        self.assertEqual('\x00\x01' + '\x00' * 14, f('1::'))
        self.assertEqual(
            '\x45\xef\x76\xcb\x00\x1a\x56\xef\xaf\xeb\x0b\xac\x19\x24\xae\xae',
            f('45ef:76cb:1a:56ef:afeb:bac:1924:aeae'))
        # Scope ID doesn't affect the binary representation.
        self.assertEqual(
            '\x45\xef\x76\xcb\x00\x1a\x56\xef\xaf\xeb\x0b\xac\x19\x24\xae\xae',
            f('45ef:76cb:1a:56ef:afeb:bac:1924:aeae%en0'))

        self.assertEqual('\x00' * 14 + '\x00\x01', f('::1'))
        self.assertEqual('\x00' * 12 + '\x01\x02\x03\x04', f('::1.2.3.4'))
        self.assertEqual(
            '\x00\x01\x00\x02\x00\x03\x00\x04\x00\x05\x00\x06\x01\x02\x03\xff',
            f('1:2:3:4:5:6:1.2.3.255'))

        for badaddr in ['1:2:3:4:5:6:7:8:', ':1:2:3:4:5:6:7:8', '1::2::3',
                        '1:::3', ':::', '1:2', '::1.2', '1.2.3.4::',
                        'abcd:1.2.3.4:abcd:abcd:abcd:abcd:abcd',
                        '1234:1.2.3.4:1234:1234:1234:1234:1234:1234',
                        '1.2.3.4', '', '%eth0']:
            self.assertRaises(ValueError, f, badaddr)

        L{twisted.python.compat.inet_pton} parses IPv4 and IPv6 addresses in a
        manner similar to that of L{socket.inet_pton}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_compat.py