Scala 发送到“TestProbe”的测试消息是否可能在“TestActor.SetAutoPilot(pilot)”之前到达`
示例表明,我们可以在调用Scala 发送到“TestProbe”的测试消息是否可能在“TestActor.SetAutoPilot(pilot)”之前到达`,scala,akka,akka-testkit,Scala,Akka,Akka Testkit,示例表明,我们可以在调用setAutoPilot后立即向TestProbe发送消息: probe.setAutoPilot(new TestActor.AutoPilot { def run(sender: ActorRef, msg: Any): TestActor.AutoPilot = msg match { case "stop" ⇒ TestActor.NoAutoPilot case x ⇒ testActor.tel
setAutoPilot
后立即向TestProbe
发送消息:
probe.setAutoPilot(new TestActor.AutoPilot {
def run(sender: ActorRef, msg: Any): TestActor.AutoPilot =
msg match {
case "stop" ⇒ TestActor.NoAutoPilot
case x ⇒ testActor.tell(x, sender); TestActor.KeepRunning
}
})
//#autopilot
probe.ref ! "hallo"
另一方面,setAutoPilot
已实现为向testActor
发送消息:
def setAutoPilot(pilot: TestActor.AutoPilot): Unit = testActor ! TestActor.SetAutoPilot(pilot)
根据,testActor(probe.ref
)无法在testActor.SetAutoPilot(pilot)
之前接收“hallo”
,因为两者都是从同一来源发送的
但是,如果我们使用第三个参与者(使用system.actorOf(…)
创建)向probe.ref
发送“hello”
在某些情况下,在
TestActor.SetAutoPilot(pilot)
之前,probe.ref
接收到它,从而最终被忽略,这不可能吗?理论上是的,肯定是的,这基本上是你自己对这个问题的回答。实际上,这是不可能的,因为另一条消息的路径更长,因此需要发生一些非常不寻常的事情,以便它能够更早到达
由于围绕这一点进行的理论研究无法给出任何可行的答案,因此我编写了一个测试来进行实证观察:
Build.sbt:
libraryDependencies ++= Seq(
"com.typesafe.akka" %% "akka-actor" % "2.5.17"
)
libraryDependencies ++= Seq(
"com.typesafe.akka" %% "akka-testkit" % "2.5.17",
"org.scalactic" %% "scalactic" % "3.0.5",
"org.scalatest" %% "scalatest" % "3.0.5",
"org.scalacheck" %% "scalacheck" % "1.14.0"
) map (_ % "test")
测试:
实际上,在第二次测试中,我一路重复了10000次,测试总是通过的——而且我还确保如果在向代理发送消息后设置了自动驾驶仪,或者如果testProbe没有响应,测试就会失败
所以,我想说,你所描述的潜在问题要么根本没有发生,要么极不可能发生。当然,该测试非常简单,因此在其他条件下(即阻塞、并行测试执行、CI等),观察结果可能不同,但至少它为最常见/简单的情况提供了一些证据
import scala.concurrent.duration.DurationInt
import akka.actor.{Actor, ActorRef, ActorSystem, Props}
import akka.pattern.ask
import akka.testkit.{TestActor, TestKit, TestProbe}
import akka.util.Timeout
import org.scalatest.{Matchers, PropSpecLike}
import org.scalatest.concurrent.ScalaFutures
import org.scalatest.prop.PropertyChecks
class AutopilotTest extends TestKit(ActorSystem("test"))
with PropSpecLike with PropertyChecks with ScalaFutures with Matchers {
private implicit val askTimeout: Timeout = Timeout(100.millis)
property("Test probe receives autopilot before any other message from same origin") {
forAll(minSuccessful(1000)) { msg: String =>
val probe = TestProbe()
probe.setAutoPilot((sender: ActorRef, msg: Any) => msg match {
case x => sender ! x; TestActor.KeepRunning
})
whenReady((probe.ref ? msg).mapTo[String]) {_ shouldBe msg}
}
}
private class ProxyActor(target: ActorRef) extends Actor {
override def receive: Receive = { case msg: Any => target forward msg }
}
private object ProxyActor { def props(target: ActorRef): Props = Props(new ProxyActor(target)) }
property("Test probe receives autopilot before any other message from other origin") {
// set minSuccessuful to as high as you want, but note that current version takes ~38 seconds on my laptop to run
forAll(minSuccessful(1000)) { msg: String =>
val probe = TestProbe()
val proxy = system.actorOf(ProxyActor.props(probe.ref))
val result = (proxy ? msg).mapTo[String]
probe.setAutoPilot((sender: ActorRef, msg: Any) => msg match {
case x => sender ! x; TestActor.KeepRunning
})
whenReady(result) {_ shouldBe msg}
}
}
}