CommonDomain - how to unit test aggregate root

Question

I have a small system that uses Jonathan Oliver's CommonDomain and EventStore.

How can I unit test my aggregate roots in order to verify that correct events are raised?

Consider following aggregate root:

public class Subscriber : AggregateBase
{
        private Subscriber(Guid id)
        {
            this.Id = id;
        }

        private Subscriber(Guid id, string email, DateTimeOffset registeredDate)
            : this(id)
        {
            this.RaiseEvent(new NewSubscriberRegistered(this.Id, email, registeredDate));
        }

        public string Email{ get; private set; }
        public DateTimeOffset RegisteredDate { get; private set; }

        public static Subscriber Create(Guid id, string email, DateTimeOffset registeredDate)
        {
            return new Subscriber(id, email, registeredDate);
        }

        private void Apply(NewSubscriberRegistered @event)
        {
            this.Email = @event.Email;
            this.RegisteredDate = @event.RegisteredDate;
        }
}

I would like to write a following test:

    // Arrange
    var id = Guid.NewGuid();
    var email = "[email protected]";
    var registeredDate = DateTimeOffset.Now;

    // Act
    var subscriber = Subscriber.Create(id, email, registeredDate);

    // Assert
    var eventsRaised = subscriber.GetEvents();  <---- How to get the events?
    // Assert that NewSubscriberRegistered event was raised with valid data

I could set up whole EventStore with memory persistence and synchronous dispatcher, hook up mock event handler and store any published events for verification, but it seems a bit of overkill.

There is an interface IRouteEvents in CommonDomain. Looks like I could mock it to get the events directly from AggregateBase but how would I actually pass it to my Subscriber class? I don't want to 'pollute' my domian with testing-related code.

Answer 1

I've found out that AggregateBase explicitly implements IAggregate interface, which exposes ICollection GetUncommittedEvents(); method.

So the unit test looks like that:

var eventsRaised = ((IAggregate)subscriber).GetUncommittedEvents();

and no dependency on EventStore is required.