def test_missingGlue(self):
        """
        If an intermediate response includes no glue records for the
        authorities, separate queries are made to find those addresses.
        """
        servers = {
            ('1.1.2.3', 53): {
                (b'foo.example.com', A): {
                    'authority': [(b'foo.example.com', Record_NS(b'ns1.example.org'))],
                    # Conspicuous lack of an additional section naming ns1.example.com
                    },
                (b'ns1.example.org', A): {
                    'answers': [(b'ns1.example.org', Record_A('10.0.0.1'))],
                    },
                },
            ('10.0.0.1', 53): {
                (b'foo.example.com', A): {
                    'answers': [(b'foo.example.com', Record_A('10.0.0.2'))],
                    },
                },
            }
        resolver = self._getResolver(servers)
        d = resolver.lookupAddress(b'foo.example.com')
        d.addCallback(getOneAddress)
        d.addCallback(self.assertEqual, '10.0.0.2')
        return d

        If an intermediate response includes no glue records for the
        authorities, separate queries are made to find those addresses.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/names/test/test_rootresolve.py