Is there a way this scenario can be coded in any other way than:

---

while(moneyGotSoFar < targetMoneyToget)

{

   // code to interface with hardware device which 
   // is taking in money
   // NOTE: moneyGotInThisBurst would be told by the 
   // hardware device software

   ... 

   // some time out code. And exception handling if 
   // no cash entered
   moneyGotSoFar += moneyGotInThisBurst;

}

---

So point is, the developers may not think upfront of these kind of cases. And this case can be a boundary condition test case - May potentially test any array overflows. Or some looping done the wrong way. Or out of memory if it has been coded in Java(Oops. Sorry :-))