public void addPayment()
{
decimal expectedPayment = 10;
Sale s = new OTCSale();
s.AddCashPayment(10);
Assert.AreEqual(expectedPayment, s.PaymentTotal);
}
public void saleChange()
{
decimal expectedChange = 2;
Sale s = new OTCSale();
MenuProduct m1 = new MenuProduct { Price = 3 };
MenuProduct m2 = new MenuProduct { Price = 5 };
s.AddSaleLineItem(m1);
s.AddSaleLineItem(m2);
s.AddCashPayment(10);
Assert.AreEqual(expectedChange, s.Change);
}