How do I unit test akka actors in Play Framework 2.2.0 Scala (spec2, Mockito)

Question

I am trying to set up some unit tests with the Play framework. A lot of my logic is built into scheduled akka actors that go off and gather data in the background. My problem is that I can't figure out how to unit test them. I literally have no clue how to approach it. I'm trying to use akka-testkit, but I'm basically flailing around. Does anyone have any suggestions on how to even approach it? Examples would be incredibly useful. This is an example of the abomination I am currently working with:

package test

import org.specs2.mutable._
import controllers.Scanner
import java.util.UUID
import org.joda.time.DateTime
import akka.testkit.TestActorRef
import play.api.Logger
import play.api.test.{FakeApplication, TestServer}
import models.PSqlEnum

class ScannerTest extends Specification {
  val appId = UUID.randomUUID()
  val app = models.App(appId, "TestApp", "TestServer", "TestComponent", "Test Description", DateTime.now(),
                       DateTime.now(), true, 3, 60, PSqlEnum("scanType", "mandatory"), "http://localhost")
  val rules = <Rule name="DivisionDataIsAvailable" elementsToCheck="DivisionDataIsAvailable"
                    ruleType="is, true, yellow" />
              <Rule name="DivisionDataLoadIsHealthy" elementsToCheck="DivisionDataLoadIsHealthy"
                    ruleType="is, true, red" />;

  "Scanner" should {
    "test something" in {
      val fakeApp = TestServer(3333)
      fakeApp.start()
      implicit val actorSystem = play.api.libs.concurrent.Akka.system(fakeApp.application)
      val scanner = TestActorRef(new Scanner(app, rules)).underlyingActor
      Logger.warn(scanner.getResponseFromWebService.toString)
      fakeApp.stop()
      1 === 1
    }
  }
}

This is obviously not really testing anything. I am basically trying to get it to get through to the 1 === 1 at this point just to see if I can get the runtime errors to stop. The errors this code is generating are these:

INFO  - Starting application default Akka system.
[info] ScannerTest
[info] Scanner should
[info] ! test something
[error]     ThrowableException: akka.actor.LocalActorRef.<init>(Lakka/actor/ActorSystemImpl;Lakka/actor/Props;Lakka/actor/InternalActorRef;Lakka/actor/ActorPath;)V (TestActorRef.scala:21)
[error] akka.testkit.TestActorRef.<init>(TestActorRef.scala:21)
[error] akka.testkit.TestActorRef$.apply(TestActorRef.scala:135)
[error] akka.testkit.TestActorRef$.apply(TestActorRef.scala:132)
[error] akka.testkit.TestActorRef$.apply(TestActorRef.scala:125)
[error] test.ScannerTest$$anonfun$1$$anonfun$apply$3.apply(ScannerTest.scala:27)
[error] test.ScannerTest$$anonfun$1$$anonfun$apply$3.apply(ScannerTest.scala:23)
[error] akka.actor.LocalActorRef.<init>(Lakka/actor/ActorSystemImpl;Lakka/actor/Props;Lakka/actor/InternalActorRef;Lakka/actor/ActorPath;)V
[error] akka.testkit.TestActorRef.<init>(TestActorRef.scala:21)
[error] akka.testkit.TestActorRef$.apply(TestActorRef.scala:135)
[error] akka.testkit.TestActorRef$.apply(TestActorRef.scala:132)
[error] akka.testkit.TestActorRef$.apply(TestActorRef.scala:125)
[error] test.ScannerTest$$anonfun$1$$anonfun$apply$3.apply(ScannerTest.scala:27)
[error] test.ScannerTest$$anonfun$1$$anonfun$apply$3.apply(ScannerTest.scala:23)
[info] Total for specification ScannerTest
[info] Finished in 86 ms
[info] 1 example, 0 failure, 1 error
[info] test.ScannerTest

I believe that I need to create a FakeApplication and use that FakeApplication's Akka.system; however, I am not sure how to do it. To be honest, I am not even sure if that is the correct approach. If I could just generate a generic Akka.system and have that work I'd be ecstatic. If anyone has any ideas on how to tackle this I'd be really appreciative.

Answer 1

Okay, I figured it out. Make sure you are using the correct version of akka-testkit. In Play 2.2.0 I was trying to use akka 2.2.M3. Obviously, that doesn't work. I had to put the correct dependencies in my Build.scala, which ended up being this:

"com.typesafe.akka" %% "akka-testkit" % "2.2.0" % "test"

My actual test code looks like this:

package test

import org.specs2.mutable._
import controllers.Scanner
import java.util.UUID
import org.joda.time.DateTime
import akka.testkit.TestActorRef
import play.api.Logger
import models.PSqlEnum
import akka.actor.ActorSystem
import com.typesafe.config.ConfigFactory
import scala.concurrent.ExecutionContext.Implicits.global

class ScannerTest extends Specification {
  val appId = UUID.randomUUID()
  val app = models.App(appId, "TestApp", "TestServer", "TestComponent", "Test Description", DateTime.now(),
                       DateTime.now(), true, 3, 60, PSqlEnum("scanType", "mandatory"), "http://localhost")
  val rules = <Rule name="DivisionDataIsAvailable" elementsToCheck="DivisionDataIsAvailable"
                    ruleType="is, true, yellow" />
              <Rule name="DivisionDataLoadIsHealthy" elementsToCheck="DivisionDataLoadIsHealthy"
                    ruleType="is, true, red" />;


  "Scanner" should {
    "test something" in {
      implicit val actorSystem = ActorSystem("testActorSystem", ConfigFactory.load())
      val scanner = TestActorRef(new Scanner(app, rules)).underlyingActor
      val response = scanner.getResponseFromWebService
      response onSuccess {
        case result => Logger.warn(result.toString)
      }
      response onFailure {
        case error => Logger.warn(error.toString)
      }
      1 === 1
    }
  }
}

Obviously again, this test isn't really doing anything. The actual test being evaluated is 1 === 1. It does print out to the log now though which means I can go back and verify datatypes and the payload of the response, and then build some actual Unit Tests. I hope someone finds this useful. Those error messages in the original question are caused by the akka-testkit dependency not being the same version as Akka though, which might be useful for someone.