C# · 12月 28, 2021

c# – 如何在Akka.NET中使用TestKit

我试图测试我的Akka.NET演员,但是对TestKit有一些麻烦,并了解它的工作原理.

由于Akka.NET目前没有用于单元测试的官方文档,所以我已经开发了Akka.NET repo代码,但是在这里使用的例子并不适用于我.

我用来参考的测试是ReceiveActorTests.cs和ReceiveActorTests_Become.cs,因为那些接近我在我的应用程序中测试的场景.

这里有一些虚拟代码:

给这个演员

public class Greeter : ReceiveActor{ public Greeter() { NotGreeted(); } private void NotGreeted() { Receive<Greeting>(msg => Handle(msg)); } private void Greeted() { Receive<Farewell>(msg => Handle(msg)); } private void Handle(Greeting msg) { if (msg.Message == “hello”) { Become(Greeted); } } private void Handle(Farewell msg) { if (msg.Message == “bye bye”) { Become(NotGreeted); } }}

我想测试它正确接收到问候和告别消息,并进入正确的状态.看看ReceiveActorTests_Become.cs测试,一个演员是由…创建的

var system = ActorSystem.Create(“test”);var actor = system.ActorOf<BecomeActor>(“become”);

并发送和断言的消息

actor.Tell(message,TestActor);ExpectMsg(message);

然而,当我尝试这种方法来实例化一个演员,还有许多其他的基于TestKit方法(见下文),我不断得到samme失败的测试错误:

Xunit.Sdk.TrueExceptionFailed: Timeout 00:00:03 while waiting for a message of type ConsoleApplication1.Greeting Expected: TrueActual: False

这是我的考验

public class XUnit_GreeterTests : TestKit{ [Fact] public void BecomesGreeted() { //var system = ActorSystem.Create(“test-system”); // Timeout error //var actor = system.ActorOf<Greeter>(“greeter”); // Timeout error //var actor = ActorOfAsTestActorRef<Greeter>(“greeter”); // Timeout error //var actor = ActorOf(() => new Greeter(),”greeter”); // Timeout error //var actor = Sys.ActorOf<Greeter>(“greeter”); // Timeout error //var actor = Sys.ActorOf(Props.Create<Greeter>(),”greeter”); // Timeout error var actor = CreateTestActor(“greeter”); // Works,but doesn’t test my Greeter actor,but rather creates a generic TestActor (as I understand it) var message = new Greeting(“hello”); actor.Tell(message,TestActor); ExpectMsg(message); }}

我也尝试将ExpectMsg行移动到actor.Tell行之上(因为在行动之前预期某事更有意义,而是验证之后的期望),但这也导致超时错误.

我已经尝试过NUnit和XUnit TestKits.

可能有一些我所忽视的真正的基础.

解决方法 TestKit用于进行更多的行为测试,以验证您的演员是否按照预期在整个演员系统的上下文中工作.这更像黑盒测试 – 你不直接到达演员的内部.相反,最好专注于给定信号A和演员行为B等行为,它应该向另一个演员D发出消息C.

在您的示例中,Greeter演员的问题是,它是静音的 – 虽然它可以接收到一些输入,但它不会在结果中做任何事情.从整个系统的角度来看,它可能会死亡,没有人会关心.

使用其他示例 – 给定以下演员:

public class Greeter : ReceiveActor{ public Greeter() { Receive<Greet>(greet => { // when message arrives,we publish it on the event stream // and send response back to sender Context.System.EventStream.Publish(greet.Who + ” sends greetings”); Sender.Tell(new GreetBack(Self.Path.Name)); }); }}

让我们创建一个示例测试规范:

public class GreeterSpec : TestKit{ private IActorRef greeter; public GreeterSpec() : base() { greeter = Sys.ActorOf<Greeter>(“TestGreeter”); } [Fact] public void Greeter_should_GreetBack_when_Greeted() { // set test actor as message sender greeter.Tell(new Greet(“John SNow”),TestActor); // ExpectMsg tracks messages received by TestActors ExpectMsg<GreetBack>(msg => msg.Who == “TestGreeter”); } [Fact] public void Greeter_should_broadcast_incoming_greetings() { // create test probe and subscribe it to the event bus var subscriber = CreateTestProbe(); Sys.EventStream.Subscribe(subscriber.Ref,typeof (string)); greeter.Tell(new Greet(“John SNow”),TestActor); // check if subscriber received a message subscriber.ExpectMsg<string>(“John SNow sends greetings”); }}

你可以看到,这里我不检查演员的内部状态.相反,我正在观察它对我发送的信号的反应,并验证它是否是预期的结果.