public void CalculateFeeTest_Buy_One_Book1_One_Book2_One_Book3_One_book4_One_book5_Should_Get_Fee_375()
        {
            PotterShoppingCart target = new PotterShoppingCart();

            var basket = new Basket
            {
                Books = new List<Book>()
                {
                    new Book() { BookId = 1 },
                    new Book() { BookId = 2 },
                    new Book() { BookId = 3 },
                    new Book() { BookId = 4 },
                    new Book() { BookId = 5 }
                }
            };

            target.CalculateFee(basket);

            var expected = 375;
            Assert.AreEqual(expected, basket.Fee);
        }
        public void CalculateFeeTest_Buy_One_Book1_Should_Get_Fee_100()
        {
            PotterShoppingCart target = new PotterShoppingCart();

            var basket = new Basket
            {
                Books = new List<Book>() { new Book() { BookId = 1 } }
            };

            target.CalculateFee(basket);

            var expected = 100;
            Assert.AreEqual(expected, basket.Fee);
        }