ScalaInAction测试——静态测试

ScalaInAction测试——静态测试

前言

首先，咱们须要了解如何测试发送和接受消息，包括发送而后无论的模式以及发送以后等待回复的交互式模式。
使用的是 Scala 的测试框架 [ScalaTest]http://www.scalatest.org/。这个框架被设计成可读性性很高。
使用这个工具能够生成可读性很强的测试报告。固然 Akka 也为咱们提供了测试工具 akka-test，若是没有这个工具，
咱们将面临相比与正常对象更加困难的测试环境。主要有下面四个缘由：

1. 没法准确把握消息到达时间，由于消息是异步发送的
2. 并发，Actors 之间是并发多线程的，须要考虑更多的问题，如锁、障碍等
3. 无状态 Actor是没法直接访问对象的，只能经过 ActorRef
4. 集成测试。若是须要集成测试多个 Actor 就须要在它们直接作拦截，这也是不明确如何去实现的

下面主要从两个方面演示如何利用 akka-testkit + ScalaTest 做测试：

1. Single threaded unit testing
2. Multi-threaded unit testing

环境搭建

安装 jdk + sbt + scala， build.sbt 中加入以下内容：

name := "testdriven" #名字随意取，项目名称

version := "0.1-SNAPSHOT"

organization := "com.manning" #公司域名倒过来写，最后能够加入部门简称

scalaVersion := "2.11.7"

libraryDependencies ++= {
  val akkaVersion       = "2.3.12"
  Seq(
    "com.typesafe.akka"       %%  "akka-actor"   % akkaVersion, #注意两个 %% 号的用法基本类
    "com.typesafe.akka"       %%  "akka-slf4j"   % akkaVersion, #日志类
    "com.typesafe.akka"       %%  "akka-testkit" % akkaVersion   % "test", #最后一个 %指定使用范围
    "org.scalatest"           %%  "scalatest"    % "2.2.4"       % "test"
  )
}

静态测试示例1

package packagename
import org.scalatest.WordSpecLike
import org.scalatest.MustMatchers
import akka.testkit.{ TestActorRef, TestKit }
import akka.actor._

package silenttest {

class SilentActorTest extends TestKit(ActorSystem("testsystem"))
    with WordSpecLike
    with MustMatchers
    with StopSystemAfterAll {

    "A Silent Actor" must {

      "change internal state when it receives a message, single" in {
        import SilentActor._

        //  利用TestActorRef 直接生成能够访问实际 Actor 对象的 Actor
        val silentActor = TestActorRef[SilentActor]
        silentActor ! SilentMessage("whisper")
        //  静态的测试方法，直接访问actor的内部对象
        silentActor.underlyingActor.state must (contain("whisper"))
      }
      //<end id="ch02-silentactor-test02"/>
    }
  }


  object SilentActor {
    case class SilentMessage(data: String)
    case class GetState(receiver: ActorRef)
  }

  class SilentActor extends Actor {
    import SilentActor._
    var internalState = Vector[String]()

    def receive = {
      case SilentMessage(data) =>
        internalState = internalState :+ data
    }

    def state = internalState
  }
}

//通用类，目的是及时关闭全部Actor
package common {
  import akka.testkit.TestKit
  import org.scalatest.{Suite, BeforeAndAfterAll}

  trait StopSystemAfterAll extends BeforeAndAfterAll{

    //注意这种混入手法
    this: TestKit with Suite =>
    override protected def afterAll(): Unit = {
      super.afterAll()
      system.shutdown()
    }
  }
}

静态测试示例2

package silentactor03 {

  class SilentActorTest extends TestKit(ActorSystem("testsystem"))
    with WordSpecLike
    with MustMatchers
    with StopSystemAfterAll {

    "A Silent Actor" must {

      "change internal state when it receives a message, multi" in {
        import SilentActor._ 

        val silentActor = system.actorOf(Props[SilentActor], "s3")
        silentActor ! SilentMessage("whisper1")
        silentActor ! SilentMessage("whisper2")
        //经过发送消息获取内部状态
        silentActor ! GetState(testActor) 
        expectMsg(Vector("whisper1", "whisper2")) 
      }

    }

  }


  object SilentActor {
    case class SilentMessage(data: String)
    case class GetState(receiver: ActorRef) 
  }

  class SilentActor extends Actor {
    import SilentActor._
    var internalState = Vector[String]()

    def receive = {
      case SilentMessage(data) =>
        internalState = internalState :+ data
      case GetState(receiver) => receiver ! internalState 
    }
  }
}

参考文献

scala in action