public void volume_discount_is_not_applied_to_less_than_10_items_percent(int numItems)
        {
            // arrange
              var expected = new Price(new Amount(Currency.DKK, 25 * numItems), new Amount(Currency.DKK, 25 * numItems) * 0.25m);
              var taxCalculator = new DanishTaxCalculationStrategy();
              var sut = new PriceWithTaxCalculator(taxCalculator, new VolumeDiscount(new SimpleTotalAmountCalculator()));
              var order = CreateOrder(sut, 25, isConsumer: true, numItems: numItems);

              // act
              var actual = order.CreateBill().Price;

              // assert
              Assert.Equal(expected, actual);
        }
        public void volume_discount_is_10_percent(int itemPrice)
        {
            // arrange
              var expected = new Price(new Amount(Currency.DKK, itemPrice * 40) * 0.9m, new Amount(Currency.DKK, itemPrice * 10) * 0.9m);
              var taxCalculator = new DanishTaxCalculationStrategy();
              var sut = new PriceWithTaxCalculator(taxCalculator, new VolumeDiscount(new SimpleTotalAmountCalculator()));
              var order = CreateOrder(sut, itemPrice, isConsumer: true, numItems: 40);

              // act
              var actual = order.CreateBill().Price;

              // assert
              Assert.Equal(expected, actual);
        }