def test_constructAuthorityFromHost(self):
        """
        L{SecondaryAuthorityService} can be constructed with a C{str} giving a
        master server address and several domains, causing the creation of a
        secondary authority for each domain and that master server address and
        the default DNS port.
        """
        primary = '192.168.1.2'
        service = SecondaryAuthorityService(
            primary, ['example.com', 'example.org'])
        self.assertEqual(service.primary, primary)
        self.assertEqual(service._port, 53)

        self.assertEqual(service.domains[0].primary, primary)
        self.assertEqual(service.domains[0]._port, 53)
        self.assertEqual(service.domains[0].domain, 'example.com')

        self.assertEqual(service.domains[1].primary, primary)
        self.assertEqual(service.domains[1]._port, 53)
        self.assertEqual(service.domains[1].domain, 'example.org')

        L{SecondaryAuthorityService} can be constructed with a C{str} giving a
        master server address and several domains, causing the creation of a
        secondary authority for each domain and that master server address and
        the default DNS port.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/names/test/test_names.py