TestKit Example (Scala)

TestKit Example (Scala)

Ray Roestenburg’s example code from his blog adapted to work with Akka 1.1.

package unit.akka

import org.scalatest.matchers.ShouldMatchers
import org.scalatest.{WordSpec, BeforeAndAfterAll}
import akka.actor.Actor._
import akka.util.duration._
import akka.testkit.TestKit
import java.util.concurrent.TimeUnit
import akka.actor.{ActorRef, Actor}
import util.Random

/**
 * a Test to show some TestKit examples
 */

class TestKitUsageSpec extends WordSpec with BeforeAndAfterAll with ShouldMatchers with TestKit {
  val system = ActorSystem()
  import system._
  val echoRef = actorOf(Props(new EchoActor))
  val forwardRef = actorOf(Props(new ForwardingActor(testActor)))
  val filterRef = actorOf(Props(new FilteringActor(testActor)))
  val randomHead = Random.nextInt(6)
  val randomTail = Random.nextInt(10)
  val headList = List().padTo(randomHead, "0")
  val tailList = List().padTo(randomTail, "1")
  val seqRef = actorOf(Props(new SequencingActor(testActor, headList, tailList)))

  override protected def afterAll(): scala.Unit = {
    stopTestActor
    echoRef.stop()
    forwardRef.stop()
    filterRef.stop()
    seqRef.stop()
  }

  "An EchoActor" should {
    "Respond with the same message it receives" in {
      within(100 millis) {
        echoRef ! "test"
        expectMsg("test")
      }
    }
  }
  "A ForwardingActor" should {
    "Forward a message it receives" in {
      within(100 millis) {
        forwardRef ! "test"
        expectMsg("test")
      }
    }
  }
  "A FilteringActor" should {
    "Filter all messages, except expected messagetypes it receives" in {
      var messages = List[String]()
      within(100 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(List("some", "more", "text"))
    }
  }
  "A SequencingActor" should {
    "receive an interesting message at some point " in {
      within(100 millis) {
        seqRef ! "something"
        ignoreMsg {
          case msg: String => msg != "something"
        }
        expectMsg("something")
        ignoreMsg {
          case msg: String => msg == "1"
        }
        expectNoMsg
      }
    }
  }
}

/**
 * An Actor that echoes everything you send to it
 */
class EchoActor extends Actor {
  def receive = {
    case msg => {
      self.reply(msg)
    }
  }
}

/**
 * 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: List[String], tail: List[String]) extends Actor {
  def receive = {
    case msg => {
      head map (next ! _)
      next ! msg
      tail map (next ! _)
    }
  }
}

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