assertTrue(callbackConnector.getServerInvoker().isStarted());
assertTrue(MultiplexServerInvoker.getSocketGroupMap().containsKey("id"));
AddressPair addressPair = new AddressPair("localhost", connectPort, "localhost", freePort);
assertTrue(MultiplexServerInvoker.getAddressPairMap().containsKey(addressPair));
callbackConnector.stop();
assertFalse(MultiplexServerInvoker.getSocketGroupMap().containsKey("id"));
assertFalse(MultiplexServerInvoker.getAddressPairMap().containsKey(addressPair));
log.info("testServerNoClients() PASSES");