Akka.NET持久性单元测试 - PersisteAll / PersistAllAsync永远不会运行

Question

我在使用PersistAll和PersistAllAsync方法的ReceivePersistentActor实现的某些单元测试中遇到问题。

问题是当使用TestKit.NUnit进行单元测试时，PersistAll / Async调用永远不会调用它们的完成回调。 Persist / Async调用工作正常但PersistAll / Async调用在单元测试之外工作正常。

这与TestKit及其尝试在CallingThreadDispatcher上运行的方式有关吗？

我不确定如何为使用PersistAll / Async的代码编写单元测试 - 由于从不调用回调（我有Sender.Tell代码），测试总是因超时而失败。

我没有做任何奇怪的事情 - 我正在使用内存日志和快照存储，这些都在默认调度程序上运行（我尝试使用调用线程调度程序，但在单元测试中没有任何工作） 。

公共接口IEvent; 公共类测试：ReceivePersistentActor {

    public class StringReceivedEvent:IEvent {}

    public Test()
    {
        Console.WriteLine("Started"); // <-- This is seen, but the next console output is not - callback is never fired
        Command<string>(message => { 
            Console.WriteLine($"Received {message}");

            PersistAll(new List<IEvent>(){new StringReceivedEvent()}, @event => {
                Console.WriteLine("Persisted event"); //<-- never see this
                Sender.Tell(true); //<-- this never gets called
            });
        });
    }

    public override string PersistenceId => "test-id";
}

[TestFixture]
public class Tests : Akka.TestKit.NUnit.TestKit
{
    IActorRef subject;

    public PublishingTests() : base(ConfigurationFactory.Load().WithFallback(Akka.TestKit.Configs.TestConfigs.DefaultConfig))
    {
    }

    [SetUp]
    public void Setup() {
        subject = ActorOf(Props.Create<Test>(), "My-Test-Actor");
    }

    [Test]
    public void Can_Persist_Event_And_Send_Completion_Reply() {

        subject.Tell("hello");
        ExpectMsg<bool>(TimeSpan.FromSeconds(15)); //<---- This times out

    }
}

Answer 1

我刚刚在一个新的.NET Core 2.0项目中尝试了你的代码（稍加修改就可以编译），它运行正常。

这是完整的复制步骤。首先在命令行/ PowerShell上：

mkdir akka-net-persistence-unit-testing-issue-so
cd akka-net-persistence-unit-testing-issue-so
# Install nunit template if not already done:
dotnet new -i NUnit3.DotNetNew.Template
dotnet new nunit -n TestProject
cd TestProject
dotnet add package Akka
dotnet add package Akka.Persistence
dotnet add package Akka.TestKit.Nunit

我现在有一个.csproj文件，如下所示：

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>netcoreapp2.0</TargetFramework>

    <IsPackable>false</IsPackable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Akka" Version="1.3.7" />
    <PackageReference Include="Akka.Persistence" Version="1.3.7" />
    <PackageReference Include="Akka.TestKit.NUnit" Version="1.3.2" />
    <PackageReference Include="nunit" Version="3.10.1" />
    <PackageReference Include="NUnit3TestAdapter" Version="3.10.0" />
    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="15.6.1" />
  </ItemGroup>

</Project>

然后，为了便于再现，我将所有代码放在一个文件中，如下所示：

using System;
using System.Collections.Generic;
using Akka.Actor;
using Akka.Configuration;
using Akka.Persistence;
using NUnit.Framework;

namespace TestProject
{
    public interface IEvent {};

    public class TestActor : ReceivePersistentActor
    {

        public class StringReceivedEvent : IEvent { }

        public TestActor()
        {
            Console.WriteLine("Started");
            Command<string>(message =>
            {
                Console.WriteLine($"Received {message}");

                PersistAll(new List<IEvent>() { new StringReceivedEvent() }, @event =>
                {
                    Console.WriteLine("Persisted event");
                    Sender.Tell(true); //<-- this is apparently getting called now!
                });
            });
        }

        public override string PersistenceId => "test-id";
    }

    [TestFixture]
    public class PublishingTests : Akka.TestKit.NUnit.TestKit
    {
        IActorRef subject;

        public PublishingTests() : base(ConfigurationFactory.Load().WithFallback(Akka.TestKit.Configs.TestConfigs.DefaultConfig))
        {
        }

        [SetUp]
        public void Setup()
        {
            subject = ActorOf(Props.Create<TestActor>(), "My-Test-Actor");
        }

        [Test]
        public void Can_Persist_Event_And_Send_Completion_Reply()
        {

            subject.Tell("hello");
            ExpectMsg<bool>(TimeSpan.FromSeconds(15)); //<---- This no longer times out :-)
        }
    }
}

然后你应该能够再次从命令行测试你的代码：

dotnet test

给出输出：

Build started, please wait...
Build completed.

Test run for C:\Source\Privat\SoTest\akka-net-persistence-unit-testing-issue-so\TestProject\bin\Debug\netcoreapp2.0\Test
Project.dll(.NETCoreApp,Version=v2.0)
Microsoft (R) Test Execution Command Line Tool Version 15.7.0-preview-20180320-02
Copyright (c) Microsoft Corporation.  All rights reserved.

Starting test execution, please wait...

Total tests: 1. Passed: 1. Failed: 0. Skipped: 0.
Test Run Successful.
Test execution time: 2,8449 Seconds

我在UntypedPersistentActor和xUnit上遇到了类似的问题，但在我将其更改为ReceivePersistentActor并重新启动Visual Studio以及其他事情之后它突然消失了，但是有太多事情一下子发生，所以不幸的是我无法为我提供了解决问题的完美答案（也是我想要解决这个问题并在此重现的原因，但我无法做到）。我希望一套完整的复制步骤和一个工作项目的精确包装版本可以帮助你...