如何在Akka actor中对Dispatch Http进行单元测试？

Question

I have a Akka actor as follows; it receives a message and returns a HTTP response.

I am having trouble testing the interaction with Dispatch Http, it is a nice library but seems difficult to test.

class Service(serviceUrl:String) extends Actor with ActorLogging {
    implicit val ec = context .dispatcher

    override def receive: Receive = {
        case Get(ids) => request(ids)
    }

    private def request(ids:Seq[Int]):Unit = {
        val requestUrl = buildRequestUrl(ids)
        val request = url(requestUrl).GET
        Http(request) pipeTo sender()
    }
}

Answer 1

One way would be to do something like this with your actor:

case class Get(ids:Seq[Int])
class Service(serviceUrl:String) extends Actor with ActorLogging {
    implicit val ec = context .dispatcher

    def receive: Receive = {
        case Get(ids) => request(ids)
    }

    def request(ids:Seq[Int]):Unit = {
        val requestUrl = buildRequestUrl(ids)
        val request = url(requestUrl).GET
        executeRequest(request) pipeTo sender()
    }

    def executeRequest(req:Req) = Http(req)

    def buildRequestUrl(ids:Seq[Int]):String = s"http://someurl.com/?ids=${ids.mkString(",")}"
}

Here, I'm providing a method, executeRequest that all it does it execute the http request and return the result. This method will be overridden in my test like so:

class ServiceTest extends TestKit(ActorSystem("test")) with SpecificationLike with Mockito with ImplicitSender{

  trait scoping extends Scope{
    def mockResult:Response
    var url:String = ""
    val testRef = TestActorRef(new Service(""){
      override def executeRequest(req:Req) = {
        url = req.toRequest.getUrl()
        Future.successful(mockResult)
      }
    })
  }

  "A request to service " should{
    "execute the request and return the response" in new scoping{
      val mockedResp = mock[Response]
      def mockResult = mockedResp
      testRef ! Get(Seq(1,2,3))
      expectMsg(mockedResp)
      url ==== s"http://someurl.com/?ids=${URLEncoder.encode("1,2,3")}"
    }
  }

It's a bit crude but can be effective.