NserviceBus.Testing not using ISagaFinder for saga

1

I have a saga that I am trying to write scenario tests for, and one type of message requires a custom finder. The finder is being called when running the saga normally but if I send that type of message to the TestableSaga from NServiceBus.Testing there is a fault and no saga is found.

We are using NHibernate for our normal Saga persistence, but I am not sure if that affects the testing in any way.

var ackResult = testableSaga.Handle(new Z3Messages.SmartphonePush.AckMessage()
{
    RecipientID = "11"
});

In this instance ackResult will have the status of faulted and I can confirm that the ISagaFinder is not being called. Here is my saga finder.

public class PushSagaFinder : ISagaFinder<PushSagaData, AckMessage>
{
    public Task<PushSagaData> FindBy(AckMessage message, ISynchronizedStorageSession storageSession, IReadOnlyContextBag context, CancellationToken cancellationToken = default)
    {
        var session = storageSession.Session();
        var orderSagaData = session.QueryOver<PushSagaData>()
            .Where(d => d.LastRecipientID == message.RecipientID)
            .SingleOrDefault();
        return Task.FromResult(orderSagaData);
    }
}

Is there some additional setup that needs to be done to get the tests to use the saga finder?

2

The testable saga is designed for unit testing, not integration testing. It’s all in memory, which is why saga finders are not invoked.

You should be able to unit-test sagas and saga finders in isolation. What’s leading you to need to test them together?

I do have another question, what’s the business scenario that requires saga finders in your case?

3

I am not trying to test the saga finder in this scenario, I am trying to test the handler for the message type that is handled by the finder. So when I call this

 var ackResult = testableSaga.Handle(new Z3Messages.SmartphonePush.AckMessage()
 {
     RecipientID = "11"
 });

It returns a fault in the ackResult and doesn’t actually call the handler for AckMessage in the saga. The reason for the finder is because the AckMessage uses a different property of the saga data to match on than the rest of the messages the saga handles. If I try to setup the mapper that way it throws an exception on startup that there are multiple properties matched in the mapper.

I guess the real question should be, how do I get the testable saga to call the handler for a message type that uses an ISagaFinder?

4

@jupham,

Now I understand what the culprit is. I reproduced the problem and raised a spike PR with a potential solution: [Spike] When using saga finders the testable saga fails by mauroservienti · Pull Request #651 · Particular/NServiceBus.Testing · GitHub

At the moment, it’s a spike. I haven’t investigated the ramifications and I dislike the test fake finders requirements. It should provide a better API.