Make it possible to create unit tests for Actors

[Xorpio]

Right now i can't create a actor inside a unit test. Take the following Actor code for example

public class TestActor : Actor
{
    public TestActor(ActorService actorService, ActorId actorId) : base(actorService, actorId)
    {
    }

    public async Task<string> GetString()
    {
        return await StateManager.GetStateAsync<string>("Test");
    }
}

And using the following unit test:

    [Test]
    public async Task CanCreateActor()
    {
        var actor = new TestActor(
            new ActorService(
                new ActorTypeInformation()
            ),
            new ActorId("Test")
        );

        Assert.IsInstanceOf<Actor>(actor);
    }

When i run the unit test it throws a NullRefference exception

Message: 
    System.NullReferenceException : Object reference not set to an instance of an object.
  Stack Trace: 
    Actor.ctor(ActorService actorService, ActorId actorId)
    TestActor.ctor(ActorService actorService, ActorId actorId) line 12
    IAMEmployeeTest.CanCreateActor() line 19
    GenericAdapter`1.GetResult()
    AsyncToSyncAdapter.Await(Func`1 invoke)
    TestMethodCommand.RunTestMethod(TestExecutionContext context)
    TestMethodCommand.Execute(TestExecutionContext context)
    SimpleWorkItem.PerformWork()

[amanbha]

@Xorpio Thanks for reporting. Will using Moq and setting them correctly for ActorService help in this case? Or do you have other suggestions in mind?

[Xorpio]

The problem is that there are some hardcoded dependencies that cannot be faked. (as far as i know). Like on this line:
https://github.com/dapr/dotnet-sdk/blob/master/src/Dapr.Actors/Runtime/Actor.cs#L42

[malotho-zz]

@Xorpio please check out this work.
https://github.com/Ignition-Group-Open-Source-Contrib/DaprDotnetActorUnitests. Code coverage, and 100% testebility on the actor.

[Xorpio]

Oh nice work. it looks like a working solution. I can look further in depth in the coming days.

[malotho-zz]

@amanbha should this issue be closed?

[amanbha]

@malotho I would suggest to keep it open to track more improvements needed in SDK itself to make it easier to write unit tests.

[malotho-zz]

@amanbha that makes sense.

[amanbha]

Keeping this open for tracking more improvements to making actor unit tests

[onionhammer]

The advice here appears very outdated... is there any examples with updated SDK references on how to do unit testing with actors?