public void ApplyIndividualDiscountRule_NoDiscount(int year)
        {
            var deviceMock = new DeviceModel
            {
                Year = year
            };
            decimal discount = DiscountHelper.ApplyIndividualDiscountRule(deviceMock);

            Assert.Equal(0.0m, discount);
        }
        public void ApplyIndividualDiscountRule_ValidDiscount(int year, decimal price,
                                                              decimal expectedDiscount)
        {
            var deviceMock = new DeviceModel
            {
                Year  = year,
                Price = price
            };
            decimal discount = DiscountHelper.ApplyIndividualDiscountRule(deviceMock);

            Assert.Equal(expectedDiscount, discount);
        }