使用 akka http 的网络套接字单元测试用例

Question

我已经使用 Akka HTTP 实现了网络套接字。我正在使用来自 Kafka 的数据并使用网络套接字发送通知。功能运行良好，但 我被困在测试用例中。

 ` private def loginNotificationRoute(): Route = {
    cors() {
      pathPrefix("notifications" / Segment) { userName =>
        get {
          handleWebSocketMessages(notificationClientFlow(userName))
        }
      }
    }
  }`

Notification Actor 从数据库读取通知并将数据发送回客户端。

`  def notificationClientFlow(userName: String): Flow[Message, Message, NotUsed] = {
    info(s"Connection Request accepted for user $userName")
    val notificationActor = actorSystem.actorOf(NotificationActor.props(userName, jsonHelper))

    val incomingMessages: Sink[Message, NotUsed] =
      Flow[Message].map {
        case TextMessage.Strict(text) => NotificationActor.IncomingMessage(text)
      }.to(Sink.actorRef(notificationActor, PoisonPill))

    val outgoingMessages: Source[Message, NotUsed] =
      Source
        .actorRef[NotificationActor.ResponseType](BUFFER_SIZE, OverflowStrategy.fail)
        .mapMaterializedValue { outgoingActor =>
          notificationActor ! NotificationActor.Connected(outgoingActor)
          NotUsed
        }
        .map {
          notificationResponse: NotificationActor.ResponseType =>
            info(s"sending notification ${notificationResponse.action}")
            TextMessage.Strict(jsonHelper.write(notificationResponse))
        }

    Flow.fromSinkAndSource(incomingMessages, outgoingMessages)
  }`

Answer 1

重新设计依赖关系

在我看来，您当前设计的最大缺点是存在对特定 actorSystem 的内在依赖性；有问题的代码行是

//actorSystem comes from the outside world!!!
val notificationActor = actorSystem.actorOf(NotificationActor.props(userName, jsonHelper))

notificationClientFlow 方法应该重新参数化，以便在参数中明确列出所有依赖项。并且不应该依赖整个 ActorSystem，而应该减少到仅 ActorRef:

def notificationClientFlow(userName: String, 
                           notificationActor : ActorRef): Flow[Message, Message, NotUsed] = {
  //notificationActor is now passed in
  //val notificationActor = actorSystem.actorOf(NotificationActor.props(userName, jsonHelper))
}

这需要在 Route 创建方法中进行类似的显式声明：

private def loginNotificationRoute(notificationActor : ActorRef)() : Route = {
  ...
  handleWebSocketMessages(notificationClientFlow(userName, notificationActor))
}

测试

现在可以使用TestKit进行测试:

class MySpec() extends TestKit(ActorSystem("MySpec")) {

  val userName = "testUser"

  val notificationActor = 
    system.actorOf(NotificationActor.props(userName, jsonHelper))

  val testFlow = notificationClientFlow(userName, notificationActor)

}

此外，因为我们明确地通过了 ActorRef 而不仅仅是 ActorSystem，我们可以使用其他高级测试功能，例如 probes:

val probe = TestProbe()

val testProbeFlow = notificationClientFlow(userName, probe.ref)

上述技术同样适用于使用 standard techniques:

测试路由

val testRoute = loginNotificationRoute(testProbe)

Get() ~> testRoute() ~> check {
  //testing assertions here
}

使用 akka http 的网络套接字单元测试用例

Unit test cases for web sockets using akka http

unit-testing

scala

websocket

akka

akka-http