test code

publicDelivery createDelivery(Order order,User deliveryPerson){
   Preconditions.checkNotNull(order.getAddress(),"order address");
   Preconditions.checkArgument(workSchedule.isOnDuty(deliveryPerson, order.getArrivalTime()),
       "%s is not on duty for %s", deliveryPerson, order);

   returnnewRealDelivery(order, deliveryPerson);
 }