Reserve/Unreserve a sales order line

The are a lot of examples about how to reserve a sales order line. But i did not find an example, where the result of the reservation has been tested.

So i had to write some code for my own. I am checking the reserved value before executing my code, and afterwards. If the reserved quantity is still the same, my job seems to have failed.

static void reserveSalesLine(Args _args)
{
    InventTransIdSumSingleStatus inventTransIdSumSingleStatus;
    SalesLine salesLine;
    InventMovement inventMovement;
    InventDim inventDim;
    InventDimParm inventDimParmCriteria;
    InventQtyReservPhysical oldReservedQty;
    InventQtyReservPhysical newReservedQty;
    InventUpd_Reservation inventUpd_Reservation;
    InventQty reserveQty;

    // Inline method to get current reserved quantity for specific inventDim
    InventQtyReservPhysical getReservedQty()
    {
        inventDimParmCriteria.initFromInventDim(inventDim);        

        inventTransIdSumSingleStatus = InventTransIdSumSingleStatus::newTransOriginIdStatus(InventTransOriginSalesLine::findInventTransOriginId(salesLine.DataAreaId, salesLine.InventTransId),
                                                                                            StatusReceipt::None,
                                                                                            StatusIssue::ReservPhysical);
        inventTransIdSumSingleStatus.parmInventDimCriteria(inventDim);
        inventTransIdSumSingleStatus.parmInventDimParmCriteria(inventDimParmCriteria);

        return inventTransIdSumSingleStatus.reservPhysical();
    }

    // Sales order line
    salesLine = SalesLine::findInventTransId('012431');
    inventMovement = InventTrans::findTransId(salesLine.InventTransId).inventMovement(true);

    // Build inventDim-Record, where the quantity should be reserved
    inventDim.clear();
    inventDim.InventSiteId      = "1";
    inventDim.InventLocationId  = "12";
    inventDim.wmsLocationId     = "12";
    inventDim = InventDim::findOrCreate(inventDim);

    // Get current physical reserved Quantity
    oldReservedQty = getReservedQty();

    // Set quanity which should be reserved (negative values to reserve, postive value to unreserve)
    reserveQty = -2;

    inventUpd_Reservation = InventUpd_Reservation::newInventDim(inventMovement,
                                                                inventDim,
                                                                reserveQty,
                                                                true);
    inventUpd_Reservation.updateNow();

    // Get new reserved quantity
    newReservedQty = getReservedQty();

    // Compare old and new reserved quantity to identify if reservation failed
    if(oldReservedQty == newReservedQty)
    {
        error("Reservation failed.");
    }
}