public void CheckUnsubscribe()
{
Assert.AreEqual(0, publisher.Observers.Count);
subscriber.Subscribe(publisher, EventType.RequestPurchaseEvent);
Assert.AreEqual(1, publisher.Observers.Count);
Assert.AreEqual(1, publisher.Observers[EventType.RequestPurchaseEvent].Count);
subscriber.Unsubscribe();
Assert.AreEqual(1, publisher.Observers.Count);
Assert.AreEqual(0, publisher.Observers[EventType.RequestPurchaseEvent].Count);
}
