GooleTest for Client/Server Testing

I've got a redis-server running and I connect to it using my customized client developed in C++ (using hiredis C interface). This client subscribes to a channel and waits for another client to publish something onto the channel. Is there any rational way of how to cover my client with the googletest unit tests? It looks obvious that I cannot test it using the synchronous API, but maybe combining the asynchronous API with the googletest event listeners I can come up with a solution? I need some sort of an icebreaking advice of how to test a typical client-server model. Thanks!