Spock mocks for Akka's ActorRef

Question

I've tried to make an Spock test for a class, where i need to check that it sends a message to actor (say statActor). I know that Akka have special library for integration test, but seems that it's too much for very simple test. So, i've tried:

setup:
def myActor = Mock(ActorRef)
myService.statActor = myActor
when:
myService.startStats()
then:
1 * myActor.tell(_)

Target method looks like:

void startStats() {
    Date x = null
    // prepare some data, fill x with required value
    this.statActor.tell(x)
}

I thought that Spock will create mock with a method tell. But after running this test i'm getting:

java.lang.ClassCastException: akka.actor.ActorRef$$EnhancerByCGLIB$$80b97938 cannot be cast to akka.actor.ScalaActorRef
    at akka.actor.ActorRef.tell(ActorRef.scala:95)
    at com.example.MyService.startStats(MyService.groovy:32)

Why it's calling real ActorRef implementation? Some kind of incompatibility with Scala? Is there any way to make mock for such class?

Piquant

"but seems that it's too much for very simple test" <-- may I ask how this conclusion is made, especially considering that the mocking you've tried didn't work out? – Cull

@ViktorKlang because one line def actor = Mock(ActorRef) is less that few dozen of lines required for testkit. I mean it can make mock for other objects, works fine and really easy to use – Piquant

@paradigmatic yes, i know. probably I'm asking hard questions, but what can I do here? :( – Piquant

Answer 1

The only supported way to mock an ActorRef is by creating a TestProbe:

// "system" is an ActorSystem
final TestProbe probe = TestProbe.apply(system);
final ActorRef mock = probe.ref;

It does not get easier or simpler than this.

Pirozzo

Thanks. How I can test that .tell() is called for this actor, with a value that i can test as well? – Piquant

There plenty of methods for asserting message reception on a probe, listed on doc.akka.io/api/akka/2.0/akka/testkit/TestProbe.html – Acarology

Oh, I was sure that it's the same as TestActorRef – Piquant

@Roland Kuhn Actually i've asked about using it with Spock. As I understand, you mean that there is not way to use standard Spock mocks for Akka, right? – Piquant

@Igor: If you want to write your own testkit for Akka, feel free. – Cull

Answer 2

In specs2 you can do:

val mockedActorRef = spy(TestProbe().ref)

Then use it as normal.

Ss