Aptitude Knowledge Question:

Answer #1
An ATM has been specified to work in the following way:
Enter a card and if the card is invalid reject the card and exit system. If it is a valid card then enter a PIN number. Check to see if the PIN is invalid
– if it is then display a message ‘invalid pin number, please re-enter’. If 3 attempts are made with an invalid pin then the machine keeps the card. If it is a valid PIN then the user can select one of the following transactions:

• Cash Withdrawal without receipt
• Cash Withdrawal with receipt
• Balance Inquiry
• Statement request
• Cancel

What tests would you produce to test this application? State any assumptions when testing


Answer:
1. Invalid Card – reject card and exit
2. Valid Card and Invalid PIN – error message ‘invalid pin…’ (then enter valid pin)
3. Valid Card and Invalid PIN – error message ‘invalid pin…’ (then enter another 2 invalid Pins)
4. Valid Card, Valid Pin & Cancel (correct length pin)
5. Valid Card, Valid Pin in a large number – but the pin number contains more than the maximum number – should error
6. Valid Card, Valid Pin & Cash Withdraw without receipt
7. Valid Card, Valid Pin & Cash Withdraw with receipt
8. Valid Card, Valid Pin & Balance inquiry
9. Valid Card, Valid Pin & Statement Request

Answer #2
10. Destructive tests include:
• Putting in 2 cards • Putting correct pin, but adding an extra number to make invalid Assumptions:
1. Can insert up to 3 invalid pins and machine retains card
2. Can only select one transaction and then have to re-insert card
3. Pressing cancel will return card