Service Fabric Unit Testing and Dependency Injection

Question

I can\'t test a Reliable Service/Actor by just calling it\'s constructor and then test it\'s methods. var testService = new SomeService(); throws a NullReferenceExc

Answer 1

For mocking the state manager in Reliable Actors, you can do something like this:

private readonly IActorStateManager _stateManager;

public MyActor(IActorStateManager stateManager = null)
{
    _stateManager = stateManager ?? this.StateManager;
}

Actually, the StateManager isn't yet initialized at this time. We can get it when OnActivateAsync is called:

private IActorStateManager _stateManager;

// Unit tests can inject mock here.
public MyActor(IActorStateManager stateManager = null)
{
    _stateManager = stateManager;
}

protected override async Task OnActivateAsync()
{
    if (_stateManager == null)
    {
        _stateManager = StateManager;
    }
}

Just make sure to always use _stateManager in the rest of the code instead of this.StateManager.