Java mock actor child

stuff.java

class MyActor extends AbstractActor {

  public Receive createReceive() {
    return receiveBuilder()
        .match(Request.class, this::onRequest)
        .build();
  }

  private void onRequest(Request request) {
    ActorRef child = createChildForRequest(request);
    // do stuff with child, for example forward request
    child.tell(request, getSender());
  }

  protected ActorRef createChildForRequest(Request request) {
    return getContext().actorOf(Child.props(), request.getId());
  }
}


class MyActorTest extends TestKit {

  public MyActorTest() {
    super(ActorSystem.create("MyActorTest"));
  }

  public void testSpawningChildOnRequest() {
    TestProbe childCreationProbe = new TestProbe(getSystem());
    ActorRef myActor = getSystem().actorOf(Props.create(() -> new MyActor() {
      @Override
      protected ActorRef createChildForRequest(Request request) {
        TestProbe pretendChild = new TestProbe(getContext().getSystem());
        childCreationProbe.ref().tell(pretendChild, ActorRef.noSender());
        return pretendChild.ref();
      }
    }));

    TestProbe senderProbe = new TestProbe(getSystem());
    myActor.tell(new Request("id1"), senderProbe.ref());
    TestProbe firstChildProbe = childCreationProbe.expectMsgClass(TestProbe.class);
    Request firstRequest = firstChildProbe.expectMsgClass(Request.class);
    assertEquals(firstRequest.getId(), "id1");
  }


}