scala - 喷雾解码泛型

Question

我正在使用 spray-client 在 e2e 测试中向我的服务器生成 http 请求。我还使用 specs2 来测试来自服务器的所需响应。一切正常。我构建了一些自定义 specs2 匹配器来简化我的测试代码。我的测试看起来像这样:

val response = get(<server_endpoint_url>)

response must beSuccessfulWith(content = expected_data)

我有一个特性可以在某种程度上简化 spray 在测试中的使用:

trait SprayTestClientSupport {
    implicit val system = ActorSystem()
    import system.dispatcher // execution context for futures

    val pipeline: HttpRequest => Future[HttpResponse] = sendReceive

    def get(url: String): Future[HttpResponse] = pipeline(Get(url))
}

我还有一个特征，我定义了我在测试中使用的自定义匹配器:

trait SprayTestClientSupport extends ShouldMatchers with SprayJsonSupport with DefaultJsonProtocol {
    def beSuccessfulWith(content: Seq[Int]): Matcher[Future[HttpResponse]] = 
      beSuccessful and haveBodyWith(content)

    def haveBodyWith(content: Seq[Int]): Matcher[Future[HttpResponse]] = 
      containTheSameElementsAs(content) ^^ { f: Future[HttpResponse] =>
        Await.result(f, await).entity.as[Seq[Int]].right.get
      }

    def beSuccessful: Matcher[Future[HttpResponse]] =
      ===(StatusCode.int2StatusCode(200)) ^^ { f: Future[HttpResponse] =>
        Await.result(f, await).status 
      } 
}

当我尝试使匹配器更通用并支持任何 Scala 类型时，我的问题就开始了。我这样定义:

def haveBodyWith[T: TypeTag](content: T): Matcher[Future[HttpResponse]] = 
  ===(content) ^^ { f: Future[HttpResponse] => 
    Await.result(f, await).entity.as[T].right.get
}

但随后我收到以下错误消息:

Error:(49, 86) could not find implicit value for parameter unmarshaller: spray.httpx.unmarshalling.Unmarshaller[T]
===(content) ^^ { (f: Future[HttpResponse]) => { Await.result(f, await).entity.as[T].right.get } }

有什么我遗漏的简单的东西吗？

谢谢!

P.S.
I use the following spray versions:
spray-client_2.10 -> 1.3.3
spray-can_2.10    -> 1.3.3
spray-http_2.10   -> 1.3.3
spray-httpx_2.10  -> 1.3.3
spray-util_2.10   -> 1.3.3
spray-json_2.10   -> 1.3.2

Answer 1

您需要为您的T 参数添加一个约束

def haveBodyWith[T: TypeTag : Unmarshaller](content: T): Matcher[Future[HttpResponse]] = 
  ===(content) ^^ { f: Future[HttpResponse] => 
     Await.result(f, await).entity.as[T].right.get
}