def test_tcp(self):
        """
        When passed a TCP strports description, L{endpoints.serverFromString}
        returns a L{TCP4ServerEndpoint} instance initialized with the values
        from the string.
        """
        reactor = object()
        server = endpoints.serverFromString(
            reactor, "tcp:1234:backlog=12:interface=10.0.0.1")
        self.assertIsInstance(server, endpoints.TCP4ServerEndpoint)
        self.assertIs(server._reactor, reactor)
        self.assertEqual(server._port, 1234)
        self.assertEqual(server._backlog, 12)
        self.assertEqual(server._interface, "10.0.0.1")

        When passed a TCP strports description, L{endpoints.serverFromString}
        returns a L{TCP4ServerEndpoint} instance initialized with the values
        from the string.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_endpoints.py