public void Edit_WhenProductDoesNotExist_ReturnNotFound() { Product obj = null; var unitOfWork = new Mock <IUnitOfWork>(); unitOfWork.Setup(i => i.ProductRepo.GetProductById(It.IsAny <int>())).Returns(obj); var controller = new DummyController(unitOfWork.Object); controller.Edit(1).Should().BeOfType(typeof(HttpNotFoundResult)); }