Created attachment 1 [details]
Branch source code

Bug reproduce:
1. Instantiate a Branch office
2. Add Orders (as test stub) to the Order Queue
3. Assign the Orders to the Courier

Expected Output:
The orders are assigned if the Queue is empty

Program Rundown:
The list is empty while the loop did not exit

In Branch.java, line 97:
    while (weight < courier.getCapacity() && thingsToSend.size() > 0) {
                                             ^
thingsToSend refers the ArrayList which will be assigned to the Courier, rather than the list of the undelivered Order Queue.