public void HotelCSVDataFeed_can_make_notification_via_Twitter() { // Arrange var notifier = MockRepository.GenerateMock <INotifier>(); var csvDataFeed = new HotelCSVDataFeed(notifier); notifier.Expect(x => x.UpdateObservers(Arg <List <IAffiliate> > .Is.Anything)) .Return("Twitter notification sent"); // Act csvDataFeed.Notify(); // Assert notifier.VerifyAllExpectations(); }