TestKit Example - Version 2.4.17

TestKit Example

Ray Roestenburg's example code from his blog adapted to work with Akka 2.x.

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 ! _ }
      }
    }
  }
}

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