public void ShouldCalculateDiscounts()
{
var result = _discountCalculator.CalculateDiscounts(_discounts.Transactions);
var expectedSmallDiscount = Constants.ShippingPrices.Small.MondialRelay - Constants.ShippingPrices.Small.LaPoste;
Assert.Equal(expectedSmallDiscount, result[1].Discount);
Assert.Equal(0, result[6].ShippingPrice);
Assert.Null(result[2].Discount);
}