public void TestServiceShouldCallRepoMethodOnce() { //Given var mockRepo = new Mock <IWatchRepository>(); var service = new WatchService(mockRepo.Object); //When mockRepo.Setup(mr => mr.RemoveMachineSubscriptionFromWatch(It.IsAny <MachineWatch>())); service.DeleteMachineSubscriptionFromWatch(new MachineWatch()); //Then mockRepo.Verify(mr => mr.RemoveMachineSubscriptionFromWatch(It.IsAny <MachineWatch>()), Times.Once); }