public void Calculate_SingleOrderItem_ShouldAddCorrectCharge()
        {
            // Arrange
            var orderItem = _orderItemBuilder.Build();
            var order     = _orderBuilder.WithOrderItems(new List <OrderItem> {
                orderItem
            }).Build();
            var expectedChargeName = ChargeName.FromBaseChargeName(_chargeName, ChargeNames.Item);

            var sut = new FixedChargeCalculator(_chargeName, new Price(CurrencyFakes.EUR, 10));

            // Act
            sut.Calculate(order);

            // Assert
            orderItem.Charges.Should()
            .HaveCount(3).And
            .ContainSingle(c => c.ChargeName.Value == expectedChargeName && c.ChargeAmount.Value == 10);
        }