public void Starting_Dns_Server_Starts_Listeners() { var mockListener = new Mocker<IDnsListener>(); var factory = new Mocker<IDnsListenerFactory>() .With(x => x.CreateListeners(), new List<IDnsListener> { mockListener.ToEntity() }) .ToEntity(); var server = new DnsServer(factory); server.StartListening(); mockListener.AssertWasCalledOnce(x => x.StartListening()); }