public void DeleteDiscountTest()
{
Discount discount = new Discount();
discount.Percent = 20;
discount.Validity = DateTime.Now;
discount.ClientId = 1000;
DiscountDAO discountDAO = new DiscountDAO();
discountDAO.AddDiscount(discount);
List <Discount> list = discountDAO.GetDiscount((int)discount.ClientId);
discount = list[list.Count - 1];
discountDAO.DeleteDiscount(discount.Id);
list = discountDAO.GetDiscount((int)discount.ClientId);
Assert.IsFalse(list.Exists(l => l.Id == discount.Id));
}