public void Payment_第1集買一本_應為100()
        {
            // arrange
            var target            = new ShoppingCart();
            var shoppingCartItems = new List <ShoppingCartItem> {
                new ShoppingCartItem(1, "哈利波特第一集", 1)
            };

            // act:結帳
            decimal actual = target.CheckOut(shoppingCartItems);

            // assert
            decimal expected = 100;

            Assert.AreEqual(expected, actual);
        }
        public void Payment_第1集買一本_第2_3集各買二本_應為460()
        {
            // arrange
            var target            = new ShoppingCart();
            var shoppingCartItems = new List <ShoppingCartItem> {
                new ShoppingCartItem(1, "哈利波特第一集", 1),
                new ShoppingCartItem(2, "哈利波特第二集", 2),
                new ShoppingCartItem(3, "哈利波特第三集", 2)
            };

            // act:結帳
            decimal actual = target.CheckOut(shoppingCartItems);

            // assert
            decimal expected = 460;

            Assert.AreEqual(expected, actual);
        }
        public void Payment_第1_2_3_4_5集各買一本_應為375()
        {
            // arrange
            var target            = new ShoppingCart();
            var shoppingCartItems = new List <ShoppingCartItem> {
                new ShoppingCartItem(1, "哈利波特第一集", 1),
                new ShoppingCartItem(2, "哈利波特第二集", 1),
                new ShoppingCartItem(3, "哈利波特第三集", 1),
                new ShoppingCartItem(4, "哈利波特第四集", 1),
                new ShoppingCartItem(5, "哈利波特第五集", 1),
            };

            // act:結帳
            decimal actual = target.CheckOut(shoppingCartItems);

            // assert
            decimal expected = 375;

            Assert.AreEqual(expected, actual);
        }