public void CheckDataQueueDequeueTypeCorrect() { IDataQueue dataQueue = new DataQueue(); var consumer = new Mock <IConsumer>(); ConsumerType inType = ConsumerType.CONSOLE; ConsumerType outType = ConsumerType.FILE; consumer.Setup(c => c.OnItemAdded()).Callback(() => outType = dataQueue.GetNextItem(inType).ConsumerType); dataQueue.RegisterListener(inType, consumer.Object); dataQueue.AddItem(new DataItem(inType, "DUMMY")); Assert.That(inType.Equals(outType), $"Expected type to be {inType} but was {outType}"); }