public void PayWithCreditCard()
        {
            string CardNumber = "1111-1111-1111-1111";
            // Day is irrelevant.
            DateTime ExiprationDate = new DateTime(1, 1, 1);
            string ZipCode = "12345";
            float Amount = 10.55F;

            CreditCardPayment payment = new CreditCardPayment(CardNumber, ExiprationDate, ZipCode, Amount);

            Assert.AreEqual(CardNumber, payment.cardNumber);
            Assert.AreEqual(ExiprationDate, payment.expirationDate);
            Assert.AreEqual(ZipCode, payment.zipCode);
            Assert.AreEqual(Amount, payment.amount);
        }
        public void AssignProperties()
        {
            string CardNumber = "1111-1111-1111-1111";
            // Day is irrelevant.
            DateTime ExiprationDate = new DateTime(1, 1, 1);
            string ZipCode = "12345";
            float Amount = 10.55F;

            CreditCardPayment payment = new CreditCardPayment(CardNumber, ExiprationDate, ZipCode, Amount);

            float ChangeInPrice = 5.0F;

            payment.amount += ChangeInPrice;

            Assert.AreEqual(Amount + ChangeInPrice, payment.amount);
        }