public void TestCaseThree()
        {
            MasterCard person1MasterCard1 = new MasterCard(100m);
            MasterCard person1MasterCard2 = new MasterCard(100m);

            WalletType person1Wallet = new WalletType();

            person1Wallet.AddCard(person1MasterCard1)
            .AddCard(person1MasterCard2);

            WalletPerson person1 = new WalletPerson();

            person1.AddWallet(person1Wallet);

            MasterCard person2MasterCard = new MasterCard(100m);
            Visa       person2Visa       = new Visa(100m);

            WalletType person2Wallet = new WalletType();

            person2Wallet.AddCard(person2MasterCard)
            .AddCard(person2Visa);

            WalletPerson person2 = new WalletPerson();

            person2.AddWallet(person2Wallet);

            Assert.Equal(10m, person1.CalculateTotalInterest());
            Assert.Equal(10m, person1Wallet.CalculateTotalInterest());
            Assert.Equal(15m, person2.CalculateTotalInterest());
            Assert.Equal(15m, person2Wallet.CalculateTotalInterest());
        }
        public void TestCaseOne()
        {
            Discover   discover   = new Discover(100m);
            MasterCard mastercard = new MasterCard(100m);
            Visa       visa       = new Visa(100m);

            WalletType wallet = new WalletType();

            wallet.AddCard(discover)
            .AddCard(mastercard)
            .AddCard(visa);

            WalletPerson person = new WalletPerson();

            person.AddWallet(wallet);

            Assert.Equal(1m, discover.CalculateTotalInterest());
            Assert.Equal(5m, mastercard.CalculateTotalInterest());
            Assert.Equal(10m, visa.CalculateTotalInterest());
            Assert.Equal(16m, person.CalculateTotalInterest());
        }