scala - 测试创建子 Actor 的 Actor

Question

例如，我有两个 Actor ——一个父 Actor 和一个子 Actor 。当 parent 收到一条消息时，它会产生与消息中指定的一样多的子actor。如何测试此功能？有没有办法模拟上下文或其他方法来检查 Actor 是否正确创建且数量正确？

class ParentActor extends Actor {
  case class CreateChildren(count: Int)

  override def receive: Receive = {
    case CreateChildren(count) => for (_ <- 0 until count) context.actorOf(Props[ChildActor])
  }
}

class ChildActor extends Actor {
  override def receive: Receive = {
    case _ =>
  }
}

更新:基于@Tim答案的解决方案
改变的类(class):

class ParentActor(childActorFactory: ChildActorFactory) extends Actor {
  override def receive: Receive = {
    case CreateChildren(count) => for (_ <- 0 until count) childActorFactory.create(context)
  }
}

object ParentActor {
  def props(childActorFactory: ChildActorFactory): Props = Props(new ParentActor(childActorFactory))
}

class ChildActorFactory {
  def create(context: ActorContext): ActorRef = context.actorOf(Props[ChildActor])
}

测试:

"ParentActor" should {
    "instantiate ten child actors" in {
      val childrenCount = 10
      val childActorFactory = mock[ChildActorFactory]
      val parentActor = TestActorRef[ParentActor](ParentActor.props(childActorFactory))

      parentActor ! CreateChildren(childrenCount)

      Mockito.verify(childActorFactory, Mockito.times(childrenCount))
        .create(parentActor.underlyingActor.context)
    }
  }

Answer 1

如果要完全测试父actor，则需要mock子actor，因此不能直接在父actor中创建子actor。相反，将工厂方法传递给父actor(依赖注入(inject)):

class ParentActor(makeChild: () => ChildActor) extends Actor {
  case class CreateChildren(count: Int)

  override def receive: Receive = {
    case CreateChildren(count) => for (_ <- 0 until count) makeChild() 
  }
}

makeChild函数可以计算创建的actor的数量。它还可以返回 ChildActor 的模拟版本实现测试行为以强调 ParentActor .