public void ActorSubscriber_should_receive_requested_elements()
{
var actorRef = Source.From(new[] { 1, 2, 3 })
.RunWith(Sink.ActorSubscriber<int>(ManualSubscriber.Props(TestActor)), Sys.Materializer());
ExpectNoMsg(200);
actorRef.Tell("ready"); //requesting 2
ExpectMsg<OnNext>().Element.Should().Be(1);
ExpectMsg<OnNext>().Element.Should().Be(2);
ExpectNoMsg(200);
actorRef.Tell("ready");
ExpectMsg<OnNext>().Element.Should().Be(3);
ExpectMsg<OnComplete>();
}