Testing Actors in Akka

Question

When i run base example for testing actors:

class MySpec(_system: ActorSystem) extends TestKit(_system) with ImplicitSender
  with WordSpec with MustMatchers with BeforeAndAfterAll {

I got error:

class WordSpec needs to be a trait to be mixed in

what am I doing wrong?

Answer 1

In ScalaTest 2.0 you can find both class and trait for WordSpec. The class named WordSpec and trait is WordSpecLike. So just use WordSpecLike instead of WordSpec:

class MySpec(_system: ActorSystem) extends TestKit(_system) with ImplicitSender
  with WordSpecLike with MustMatchers with BeforeAndAfterAll {

Answer 2

In addition to what 1esha proposed, there's one more solution in akka documentation

If for some reason it is a problem to inherit from TestKit due to it being a concrete class instead of a trait, there’s TestKitBase:

import akka.testkit.TestKitBase

class MyTest extends TestKitBase {
  implicit lazy val system = ActorSystem()

  // put your test code here ...

  shutdown(system)
}

The implicit lazy val system must be declared exactly like that (you can of course pass arguments to the actor system factory as needed) because trait TestKitBase needs the system during its construction.

Answer 3

As of Scalatest 2.0, the Specs you mix in are now classes not traits. Which means you can't use them with Akka's test kit... both are classes and you can only extend one of them.

Switch to scalatest 1.9.1. It's still supported by them and is the last version that released before they made that change and broke things for akka users. In 1.9.1, the specs are still traits.