scala - 如何测试返回 Future 的方法？

Question

我想测试一个返回 Future 的方法.我的尝试如下:

import  org.specs2.mutable.Specification
import scala.concurrent.ExecutionContext.Implicits.global
import scala.util.{Failure, Success}

class AsyncWebClientSpec extends Specification{

  "WebClient when downloading images" should {
    "for a valid link return non-zero content " in {
      val testImage = AsyncWebClient.get("https://www.google.cz/images/srpr/logo11ww.png")
      testImage.onComplete { res => 
        res match {
          case Success(image) => image must not have length(0)
          case _ =>
        }
        AsyncWebClient.shutDown
      }
    }
  }
}

除了我无法使这段代码正常工作之外，我猜可能有更好的方法来使用 Future 测试 future 。面向匹配器。

如何在specs2中正确执行？

Answer 1

Await 是一种反模式。永远不应该使用它。
您可以使用 ScalaFutures 等特征, IntegrationPatience , 和 Eventually .whenReady做你正在寻找的魔法。
例子:

import org.specs2.mutable.Specification
import scala.concurrent.ExecutionContext.Implicits.global
import scala.util.{Failure, Success}
import org.scalatest.concurrent.{IntegrationPatience, ScalaFutures}
import scala.concurrent.Future

class AsyncWebClientSpec extends Specification
    with ScalaFutures
    with IntegrationPatience {

    "WebClient when downloading images" should {

        "for a valid link return non-zero content " in {

            whenReady(Future.successful("Done")){ testImage =>

                testImage must be equalTo "Done"           
                // Do whatever you need
            }

        }
    }
}