I have successfully built a thin client/server using Qt\'s Tcp Sockets API. I know it works very well, because I have sent plenty of data over the wire and verified it. Howeve
You could be connecting to an instance of the server started earlier. Poke around with a process monitor to make sure you don't have any stray instances. Does your test setup automatically kick off and shutdown the dummy server? It could be that the test is succesfully starting the server, but failing to kill it.
Also, from the 127.0.0.1, the dummy server is running on the same machine as the test code right?