public void TestPriceUpdateWithBulk()
{
var item = new SaleItem('A', 1.00, Tuple.Create(6, 3.00));
item.UpdatePrice(1.00, Tuple.Create(3, 1.00));
var quantity = 7;
var expectedPrice = 3.00;
var actualPrice = item.PriceAtQuantity(quantity);
Assert.AreEqual(expectedPrice, actualPrice, delta: expectedPrice / 100);
}