final ActorRef client = system.actorOf(Props.create(Client.class, listen, getRef()), "client1");
final Connected c1 = expectMsgClass(Connected.class);
final Connected c2 = expectMsgClass(Connected.class);
assert c1.localAddress().equals(c2.remoteAddress());
assert c2.localAddress().equals(c1.remoteAddress());
client.tell(ByteString.fromString("hello"), getRef());
final ByteString reply = expectMsgClass(ByteString.class);
assert reply.utf8String().equals("hello");