Question

我遇到了一个扩展Stash的actor的问题，并且在一个简单的ActorSystem中使用actorOf实例化它时效果非常好。现在我真的想在我的程序中使用它们之前为我的存储演员编写一些测试。但是我无法找到在我的测试套件中使用TestActorRef和这个actor的方法。

有效的代码如下所示：

import akka.actor.{Stash, Actor, ActorSystem, Props}
import com.typesafe.config.ConfigFactory

object StashTest {
  val config = ConfigFactory.parseString(
    """
      |akka.actor.default-mailbox {
      | mailbox-type = "akka.dispatch.UnboundedDequeBasedMailbox"
      |}
    """.stripMargin)
}

class StashTestActor extends Stash {

  def receive: Actor.Receive = {
    case "unstash" =>
      unstashAll()
      context become print
    case msg => stash()
  }

  def print: Actor.Receive = {
    case msg => println(s"Unstashed message: $msg")
  }
}

val system = ActorSystem("stashSystem", StashTest.config)
val ref = system.actorOf(Props[StashTestActor])

ref ! "stash me"
ref ! "blah"
ref ! "unstash"

打印

Unstashed message: stash me

Unstashed message: blah

但是，如果我尝试为这个演员编写一个WordSpec测试，它会给我留下一些令人讨厌的异常，我无法弄清楚他们希望我在代码中改变什么。

测试类看起来像这样

import akka.testkit.{TestActorRef, TestKit}
import akka.actor.{Stash, Actor, ActorSystem}
import org.scalatest.{WordSpecLike, MustMatchers}
import com.typesafe.config.ConfigFactory


class StashTestActor extends Stash {

  def receive: Actor.Receive = {
    case "unstash" =>
      unstashAll()
      context become print
    case msg => stash()
  }

  def print: Actor.Receive = {
    case msg => println(s"Unstashed message: $msg")
  }
}


class StashTest extends TestKit(ActorSystem("testSystem", StashTest.config))
with WordSpecLike
with MustMatchers {

  "A simple stashing actor" must {
    val actorRef = TestActorRef[StashTestActor]

    "stash messages" in {
      actorRef ! "stash me!"
    }

    "unstash all messages" in {
      actorRef ! "unstash"
    }
  }
}

object StashTest {
  val config = ConfigFactory.parseString(
    """
      |akka.actor.default-mailbox {
      | mailbox-type = "akka.dispatch.UnboundedDequeBasedMailbox"
      |}
    """.stripMargin)
}

运行测试时，我会得到以下在TestActorRef实例化期间抛出的异常。

[ERROR] [08/20/2013 14:19:40.765] [testSystem-akka.actor.default-dispatcher-3] [akka://testSystem/user/$$a] Could not instantiate Actor
Make sure Actor is NOT defined inside a class/trait,
if so put it outside the class/trait, f.e. in a companion object,
OR try to change: 'actorOf(Props[MyActor]' to 'actorOf(Props(new MyActor)'.
akka.actor.ActorInitializationException: exception during creation
    at akka.actor.ActorInitializationException$.apply(Actor.scala:218)
    at akka.actor.ActorCell.create(ActorCell.scala:578)
    at akka.actor.ActorCell.invokeAll$1(ActorCell.scala:425)
    at akka.actor.ActorCell.systemInvoke(ActorCell.scala:447)
    at akka.dispatch.Mailbox.processAllSystemMessages(Mailbox.scala:262)
    at akka.testkit.CallingThreadDispatcher.process$1(CallingThreadDispatcher.scala:244)
    at akka.testkit.CallingThreadDispatcher.runQueue(CallingThreadDispatcher.scala:284)
    at akka.testkit.CallingThreadDispatcher.register(CallingThreadDispatcher.scala:153)
    at akka.dispatch.MessageDispatcher.attach(AbstractDispatcher.scala:133)
    at akka.actor.dungeon.Dispatch$class.start(Dispatch.scala:84)
    at akka.actor.ActorCell.start(ActorCell.scala:338)
    at akka.testkit.TestActorRef.<init>(TestActorRef.scala:50)
    at akka.testkit.TestActorRef$.apply(TestActorRef.scala:141)
    at akka.testkit.TestActorRef$.apply(TestActorRef.scala:137)
    at akka.testkit.TestActorRef$.apply(TestActorRef.scala:146)
    at akka.testkit.TestActorRef$.apply(TestActorRef.scala:144)
    at stashActorTest.StashTest$$anonfun$1.apply$mcV$sp(StashTestActor.scala:29)
    at stashActorTest.StashTest$$anonfun$1.apply(StashTestActor.scala:28)
    at stashActorTest.StashTest$$anonfun$1.apply(StashTestActor.scala:28)
    at org.scalatest.SuperEngine.registerNestedBranch(Engine.scala:613)
    at org.scalatest.WordSpecLike$class.org$scalatest$WordSpecLike$$registerBranch(WordSpecLike.scala:120)
    at org.scalatest.WordSpecLike$$anon$2.apply(WordSpecLike.scala:851)
    at org.scalatest.words.MustVerb$StringMustWrapperForVerb$class.must(MustVerb.scala:189)
    at org.scalatest.matchers.MustMatchers$StringMustWrapper.must(MustMatchers.scala:6167)
    at stashActorTest.StashTest.<init>(StashTestActor.scala:28)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at java.lang.Class.newInstance(Class.java:374)
    at org.scalatest.tools.Framework$ScalaTestTask.execute(Framework.scala:444)
    at sbt.TestRunner.runTest$1(TestFramework.scala:84)
    at sbt.TestRunner.run(TestFramework.scala:94)
    at sbt.TestFramework$$anon$2$$anonfun$$init$$1$$anonfun$apply$8.apply(TestFramework.scala:224)
    at sbt.TestFramework$$anon$2$$anonfun$$init$$1$$anonfun$apply$8.apply(TestFramework.scala:224)
    at sbt.TestFramework$.sbt$TestFramework$$withContextLoader(TestFramework.scala:212)
    at sbt.TestFramework$$anon$2$$anonfun$$init$$1.apply(TestFramework.scala:224)
    at sbt.TestFramework$$anon$2$$anonfun$$init$$1.apply(TestFramework.scala:224)
    at sbt.TestFunction.apply(TestFramework.scala:229)
    at sbt.Tests$$anonfun$7.apply(Tests.scala:196)
    at sbt.Tests$$anonfun$7.apply(Tests.scala:196)
    at sbt.std.Transform$$anon$3$$anonfun$apply$2.apply(System.scala:45)
    at sbt.std.Transform$$anon$3$$anonfun$apply$2.apply(System.scala:45)
    at sbt.std.Transform$$anon$4.work(System.scala:64)
    at sbt.Execute$$anonfun$submit$1$$anonfun$apply$1.apply(Execute.scala:237)
    at sbt.Execute$$anonfun$submit$1$$anonfun$apply$1.apply(Execute.scala:237)
    at sbt.ErrorHandling$.wideConvert(ErrorHandling.scala:18)
    at sbt.Execute.work(Execute.scala:244)
    at sbt.Execute$$anonfun$submit$1.apply(Execute.scala:237)
    at sbt.Execute$$anonfun$submit$1.apply(Execute.scala:237)
    at sbt.ConcurrentRestrictions$$anon$4$$anonfun$1.apply(ConcurrentRestrictions.scala:160)
    at sbt.CompletionService$$anon$2.call(CompletionService.scala:30)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:724)
Caused by: akka.actor.ActorInitializationException: Could not instantiate Actor
Make sure Actor is NOT defined inside a class/trait,
if so put it outside the class/trait, f.e. in a companion object,
OR try to change: 'actorOf(Props[MyActor]' to 'actorOf(Props(new MyActor)'.
    at akka.actor.ActorInitializationException$.apply(Actor.scala:218)
    at akka.testkit.TestActorRef$$anonfun$apply$2$$anonfun$apply$1.applyOrElse(TestActorRef.scala:148)
    at akka.testkit.TestActorRef$$anonfun$apply$2$$anonfun$apply$1.applyOrElse(TestActorRef.scala:147)
    at scala.runtime.AbstractPartialFunction.apply(AbstractPartialFunction.scala:33)
    at scala.util.Failure$$anonfun$recover$1.apply(Try.scala:185)
    at scala.util.Try$.apply(Try.scala:161)
    at scala.util.Failure.recover(Try.scala:185)
    at akka.testkit.TestActorRef$$anonfun$apply$2.apply(TestActorRef.scala:147)
    at akka.testkit.TestActorRef$$anonfun$apply$2.apply(TestActorRef.scala:153)
    at akka.actor.CreatorFunctionConsumer.produce(Props.scala:369)
    at akka.actor.Props.newActor(Props.scala:323)
    at akka.actor.ActorCell.newActor(ActorCell.scala:534)
    at akka.actor.ActorCell.create(ActorCell.scala:560)
    ... 58 more
Caused by: java.lang.NullPointerException
    at akka.actor.UnrestrictedStash$class.$init$(Stash.scala:82)
    at stashActorTest.StashTestActor.<init>(StashTestActor.scala:9)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at akka.actor.ReflectiveDynamicAccess$$anonfun$createInstanceFor$2.apply(DynamicAccess.scala:78)
    at scala.util.Try$.apply(Try.scala:161)
    at akka.actor.ReflectiveDynamicAccess.createInstanceFor(DynamicAccess.scala:73)
    ... 64 more

将TestActorRefs与不扩展Stash的actor一起使用时没有任何问题。所以我不知道这是配置错误还是其他我错过的东西。

Answer 1

TestActorRef不能与Stash一起使用。 TestActorRef需要一个CallingThreadMailbox，而Stash需要DequeBasedMessageQueueSemantics。 The documentation should include this limitation and the error messages should be improved

Answer 2

我能够像Stash一样用Stash测试演员：

val actor = TestActorRef(Props(new MyActorWithStash()).withDispatcher("deque"))

Answer 3

使用默认的akka调度程序，我可以使用Stash和TestActorRef：

val myActor = TestActorRef[MyActor](Props(classOf[MyActor]).withDispatcher("akka.actor.default-dispatcher"))

请注意，这意味着您的测试将不再使用默认CallingThreadDispatcher，并且会失去突出显示的优势in the akka docs

测试将Stash与TestActorRef混合的Akka actor

3 个答案: