TestKit Example

import scala.util.Random

import org.scalatest.BeforeAndAfterAll
import org.scalatest.WordSpecLike
import org.scalatest.Matchers

import com.typesafe.config.ConfigFactory

import akka.actor.Actor
import akka.actor.ActorRef
import akka.actor.ActorSystem
import akka.actor.Props
import akka.testkit.{ TestActors, DefaultTimeout, ImplicitSender, TestKit }
import scala.concurrent.duration._
import scala.collection.immutable

/**
 * a Test to show some TestKit examples
 */
class TestKitUsageSpec
  extends TestKit(ActorSystem(
    "TestKitUsageSpec",
    ConfigFactory.parseString(TestKitUsageSpec.config)))
  with DefaultTimeout with ImplicitSender
  with WordSpecLike with Matchers with BeforeAndAfterAll {
  import TestKitUsageSpec._

  val echoRef = system.actorOf(TestActors.echoActorProps)
  val forwardRef = system.actorOf(Props(classOf[ForwardingActor], testActor))
  val filterRef = system.actorOf(Props(classOf[FilteringActor], testActor))
  val randomHead = Random.nextInt(6)
  val randomTail = Random.nextInt(10)
  val headList = immutable.Seq().padTo(randomHead, "0")
  val tailList = immutable.Seq().padTo(randomTail, "1")
  val seqRef =
    system.actorOf(Props(classOf[SequencingActor], testActor, headList, tailList))

  override def afterAll {
    shutdown()
  }

  "An EchoActor" should {
    "Respond with the same message it receives" in {
      within(500 millis) {
        echoRef ! "test"
        expectMsg("test")
      }
    }
  }
  "A ForwardingActor" should {
    "Forward a message it receives" in {
      within(500 millis) {
        forwardRef ! "test"
        expectMsg("test")
      }
    }
  }
  "A FilteringActor" should {
    "Filter all messages, except expected messagetypes it receives" in {
      var messages = Seq[String]()
      within(500 millis) {
        filterRef ! "test"
        expectMsg("test")
        filterRef ! 1
        expectNoMsg
        filterRef ! "some"
        filterRef ! "more"
        filterRef ! 1
        filterRef ! "text"
        filterRef ! 1

        receiveWhile(500 millis) {
          case msg: String => messages = msg +: messages
        }
      }
      messages.length should be(3)
      messages.reverse should be(Seq("some", "more", "text"))
    }
  }
  "A SequencingActor" should {
    "receive an interesting message at some point " in {
      within(500 millis) {
        ignoreMsg {
          case msg: String => msg != "something"
        }
        seqRef ! "something"
        expectMsg("something")
        ignoreMsg {
          case msg: String => msg == "1"
        }
        expectNoMsg
        ignoreNoMsg
      }
    }
  }
}

object TestKitUsageSpec {
  // Define your test specific configuration here
  val config = """
    akka {
      loglevel = "WARNING"
    }
    """

  /**
   * An Actor that forwards every message to a next Actor
   */
  class ForwardingActor(next: ActorRef) extends Actor {
    def receive = {
      case msg => next ! msg
    }
  }

  /**
   * An Actor that only forwards certain messages to a next Actor
   */
  class FilteringActor(next: ActorRef) extends Actor {
    def receive = {
      case msg: String => next ! msg
      case _           => None
    }
  }

  /**
   * An actor that sends a sequence of messages with a random head list, an
   * interesting value and a random tail list. The idea is that you would
   * like to test that the interesting value is received and that you cant
   * be bothered with the rest
   */
  class SequencingActor(next: ActorRef, head: immutable.Seq[String],
                        tail: immutable.Seq[String]) extends Actor {
    def receive = {
      case msg => {
        head foreach { next ! _ }
        next ! msg
        tail foreach { next ! _ }
      }
    }
  }
}