public void TestApplyRewards(decimal price, int quantity, decimal expectedTotalDiscount, PromotionReward[] rewards)
{
var currency = new Currency(Language.InvariantLanguage, "USD");
var lineItem = new LineItem(currency, Language.InvariantLanguage)
{
ProductId = ExistingProductId
};
lineItem.ListPrice = new Money(price, currency);
lineItem.SalePrice = lineItem.ListPrice;
lineItem.Quantity = quantity;
lineItem.ApplyRewards(rewards);
Assert.Equal(expectedTotalDiscount, lineItem.DiscountAmount.Amount);
}