public void RemoveDiscount()
{
Discount expected = new Discount("D104", DiscountTypeEnum.Hidden, DateTime.Parse("01/01/2018"), DateTime.Parse("31/12/2018"), 50, true);
handler.AddDiscount(expected);
Discount find = handler.GetDiscount("D104");
Assert.IsTrue(expected.Equals(find));
handler.RemoveDiscount(expected);
find = handler.GetDiscount("D104");
Assert.IsNull(find);
}
