public void If_Scan_A_Then_Price_is_50()
{
ICheckout co = new Checkout(new PricingEngine());
co.GetPricingEngine().AddQuantityPricingRule(new QuantityPricingRule("A", 50));
co.Scan("A");
decimal price = co.GetTotalPrice();
decimal expectedPrice = 50;
Assert.AreEqual(expectedPrice, price);
}