public void Can_Checkout_And_Submit_Order()
        {
            // Arrange - create a mock order processor
            Mock <IOrderProcessor> mock = new Mock <IOrderProcessor>();
            // Arrange - create a cart with an item
            Cart cart = new Cart();

            cart.AddItem(new Product(), 1);
            // Arrange - create an instance of the controller
            CartController target = new CartController(null, mock.Object);
            // Act - try to checkout
            ViewResult result = target.Chekout(cart, new ShippingDetails());

            // Assert - check that the order has been passed on to the processor
            mock.Verify(m => m.ProcessOrder(It.IsAny <Cart>(), It.IsAny <ShippingDetails>()),
                        Times.Once());
            // Assert - check that the method is returning the Completed view
            Assert.AreEqual("Completed", result.ViewName);
            // Assert - check that I am passing a valid model to the view
            Assert.AreEqual(true, result.ViewData.ModelState.IsValid);
        }
        public void Cannot_Checkout_Empty_Cart()
        {
            // Arrange - create a mock order processor
            Mock <IOrderProcessor> mock = new Mock <IOrderProcessor>();
            // Arrange - create an empty cart
            Cart cart = new Cart();
            // Arrange - create shipping details
            ShippingDetails shippingDetails = new ShippingDetails();
            // Arrange - create an instance of the controller
            CartController target = new CartController(null, mock.Object);
            // Act
            ViewResult result = target.Chekout(cart, shippingDetails);

            // Assert - check that the order hasn't been passed on to the processor
            mock.Verify(m => m.ProcessOrder(It.IsAny <Cart>(), It.IsAny <ShippingDetails>()),
                        Times.Never());
            // Assert - check that the method is returning the default view
            Assert.AreEqual("", result.ViewName);
            // Assert - check that I am passing an invalid model to the view
            Assert.AreEqual(false, result.ViewData.ModelState.IsValid);
        }
        public void Cannot_Checkout_Invalid_ShippingDetails()
        {
            // Arrange - create a mock order processor
            Mock <IOrderProcessor> mock = new Mock <IOrderProcessor>();
            // Arrange - create a cart with an item
            Cart cart = new Cart();

            cart.AddItem(new Product(), 1);
            // Arrange - create an instance of the controller
            CartController target = new CartController(null, mock.Object);

            // Arrange - add an error to the model
            target.ModelState.AddModelError("error", "error");
            // Act - try to checkout
            ViewResult result = target.Chekout(cart, new ShippingDetails());

            // Assert - check that the order hasn't been passed on to the processor
            mock.Verify(m => m.ProcessOrder(It.IsAny <Cart>(), It.IsAny <ShippingDetails>()),
                        Times.Never());
            // Assert - check that the method is returning the default view
            Assert.AreEqual("", result.ViewName);
            // Assert - check that I am passing an invalid model to the view
            Assert.AreEqual(false, result.ViewData.ModelState.IsValid);
        }