如何使用 Akka TestKit 响应失败的 Ask 模式？

Question

我有一个 Akka Actor，它使用 Ask 模式从子 actor 中检索 Future 并对成功和失败进行操作。我不知道如何模仿儿童演员并以失败回应。

代码如下：

import java.util.concurrent.TimeUnit
import akka.actor.{Actor, ActorRef, ActorSystem, Props}
import akka.pattern.ask
import akka.testkit.{ImplicitSender, TestKitBase, TestProbe}
import akka.util.Timeout
import org.specs2.mutable.Specification
import org.specs2.specification.Scope
import scala.util.{Failure, Success}

class Parent(child: ActorRef) extends Actor {
  implicit val timeout = Timeout(5, TimeUnit.SECONDS)
  import context.dispatcher

  override def receive: Receive = {
    case "go" => {
      val senderRef = sender()
      (child ? "question").mapTo[String] onComplete {
        case Success("answer") =>
          senderRef ! "child responded with a successful answer"
        case Failure(throwable) =>
          senderRef ! "child responded with a failure"
      }
    }
  }
}

class SimplifiedProblemSpec extends Specification {

  "The Parent Actor" should {
    "act on success" in new TestScope {
      parent ! "go"
      childProbe.expectMsg("question")
      childProbe.reply("answer")
      expectMsg("child responded with a successful answer")
    }
    "act on failure" in new TestScope {
      parent ! "go"
      childProbe.expectMsg("question")
      // How to reply with failure?
      expectMsg("child responded with a failure")
    }
  }

}

abstract class TestScope extends Scope with TestKitBase with ImplicitSender {
  implicit lazy val system: ActorSystem = ActorSystem()

  val childProbe = TestProbe()
  val parent = system.actorOf(Props(classOf[Parent], childProbe.ref), "Parent")

}

如有任何帮助，我们将不胜感激。

谢谢

Answer 1

您可以使用 akka.actor 包中的 Status.Failure 个案例 class。来自文档：

This class/message type is preferably used to indicate failure of some operation performed. As an example, it is used to signal failure with AskSupport is used (ask/?).

Answer 2

老实说，我不是 100% 确定这就是您要的，但以防万一您可以尝试这样的操作：

case class FailureMessage(message: String) extends Exception(message)

object MyActor {
    def props = Props(classOf[MyActor])
}

class MyActor extends Actor {
    override def receive = {
        case "cool" => sender ! Status.Success("cool")
        case boom => sender ! Status.Failure(FailureMessage("boom"))
   }
}

class MyActorSpec extends TestKit(ActorSystem("system")) with ImplicitSender with WordSpecLike with Matchers {

  implicit val timeout = Timeout(1 second)

  override def afterAll = TestKit.shutdownActorSystem(system)

  "system" must {
      "return Failure if boom" in {
          val actor = system.actorOf(MyActor.props)
          actor ! "boom"
          expectMsg(Status.Failure(FailureMessage("boom")))
      }
  }

如何使用 Akka TestKit 响应失败的 Ask 模式？

How to respond to an Ask pattern with a failure using Akka TestKit?

scala

akka

akka-testkit