def test_lookupAddress(self):
        """
        L{root.Resolver.lookupAddress} looks up the I{A} records for the
        specified hostname by first querying one of the root servers the
        resolver was created with and then following the authority delegations
        until a result is received.
        """
        servers = {
            ('1.1.2.3', 53): {
                (b'foo.example.com', A): {
                    'authority': [(b'foo.example.com', Record_NS(b'ns1.example.com'))],
                    'additional': [(b'ns1.example.com', Record_A('34.55.89.144'))],
                    },
                },
            ('34.55.89.144', 53): {
                (b'foo.example.com', A): {
                    'answers': [(b'foo.example.com', Record_A('10.0.0.1'))],
                    }
                },
            }
        resolver = self._getResolver(servers)
        d = resolver.lookupAddress(b'foo.example.com')
        d.addCallback(getOneAddress)
        d.addCallback(self.assertEqual, '10.0.0.1')
        return d

        L{root.Resolver.lookupAddress} looks up the I{A} records for the
        specified hostname by first querying one of the root servers the
        resolver was created with and then following the authority delegations
        until a result is received.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/names/test/test_rootresolve.py