public void add_sli_with_same_product_will_change_quantity()
{
var sale = new Sale();
sale.AddLineItem(momogi, 2);
Assert.AreEqual(1, sale.LineItems.Count);
sale.AddLineItem(momogi);
Assert.AreEqual(1, sale.LineItems.Count);
var sli = sale.GetLineItem(momogi);
Assert.AreEqual(3, sli.Quantity);
}
