Simple test on PersistentActor raise timeout exception

FakeActor.cs

public class FakeActor : ReceivePersistentActor
{
    public override string PersistenceId { get; } = "HashCoded";

    public FakeActor()
    {
        Command<FakeRequest>(request =>
        {
            Sender.Tell(new FakeResponse(requestId: request.RequestId));
        });
    }
}

FakeActorTest.cs

[TestFixture]
public class FakeActorTest : TestKit
{
    [Test]
    public void FakeActor_FakeRequest()
    {
        // Arrange
        var senderProbe = CreateTestProbe();
        var sut = Sys.ActorOf(Props.Create<FakeActor>());

        // Act
        sut.Tell(new FakeRequest(1), senderProbe.Ref);

        // Assert
        senderProbe.ExpectMsg<FakeResponse>(r => r.RequestId == 1);
    }
}

FakeRequest.cs

public class FakeRequest
{
    public FakeRequest(ulong requestId) { RequestId = requestId; }
    public override string ToString() => $"FakeRequest: {RequestId}";
    public ulong RequestId { get; private set; }
}

FakeResponse.cs

public class FakeResponse
{
    public FakeResponse(ulong requestId) { RequestId = requestId; }
    public override string ToString() => $"FakeResponse: {RequestId}";
    public ulong RequestId { get; private set; }
}