public void UploadImage_Negative() { Image image = new Image() { ImageId = 20, RoomId = 10, RoomImage = new Byte[1] { Convert.ToByte(12) } }; var MockRoomBusiness = new Mock <RoomManager>(); var returnType = new Acknowledgement <Image> { code = 2, Set = null, Message = "Failed to Upload Images", }; List <byte[]> list = new List <byte[]>(); list.Add(image.RoomImage); MockRoomBusiness.Setup(p => p.AddImage(list)).Throws <System.Exception>(); RoomsController roomsController = new RoomsController(MockRoomBusiness.Object); var actualReturnType = roomsController.Upload() as OkObjectResult; Assert.ReferenceEquals(returnType, actualReturnType.Value); }