public void SingleMultibuy()
{
var basket = new List <BasketItem>()
{
new BasketItem("A", 3, 50M)
};
var promotions = new List <Promotion>()
{
new Promotion("3A for 130", Promotions.MakeMultibuy("A", 3, 130M))
};
var result = Promotions.TotalAfterPromotions(basket, promotions);
result.Should().Be(130);
}
