Usage of akka ActorContext in integration tests

Question

We're migrating our project to typed akka Actors. We have services that can create actors at will, something like:

class Service(ac: ActorContext[_])
   def action() = { 
     ac.spawn(MyBehavior().receive)
  }
}

The problem arises when we're trying to test this service. It seems that we should only use testKit.spawn or testKit.createTestProbe methods. It works fine for unit-testing our classes.

But there is no way to get ActorContext[_] to pass it to services that are being tested.

So, it seems that that we are misusing the ActorContext in our service. But how a service can create a new actor?

I have an idea of passing a special ActorRef[CreateActor] that can create those actor. This way we can remove the dependency on ActorContext[_] in the Service, but I wanted to see if there is a better option.

Answer 1

First of all, you should not be passing ActorContext around, as many of the methods exposed in context are not thread safe.

You can create single ActorSystem[SpawnProtocol.Command] per JVM and pass around that to your services.

Then you can send Spawn command which takes typed actor behavior to injected actorSystem.

val echoActor: Future[ActorRef[Echo]] = actorSustem ? { replyTo: ActorRef[ActorRef[Echo]] =>  Spawn(echoBehavior, "echo-actor", Props.empty, replyTo)}

Do you really need to create actors from the service though? Maybe you can have top level wiring where you create all the necessary actors and then inject ActorRef to your services.

Off-course if your actors are short lived and gets created and destroyed based on the demand, then what I suggested above makes sense.