Let’s say you are working for a company that manufacturers soda machines. Your job is to test the machine. How would you do that? Walk me through your test cases.

I wrote up some test plans, but I may need to rewrite the plans depending on the answer of the following questions.

  1. What country is the machine going to be used in? US?
  2. Does it dispense cans or bottles or paper cup?
  3. Does the machine accept credit cards or cell phone payments?
  4. Does it have buttons or a touch screen?

Test Plans
Turns on after plugging it, and test to turn off.
Display issues (Soda machine should have the following components displayed).

  • dispense button
  • coin return button
  • dispenser
  • coin return dispenser
  • coin slot
  • bill slot
  • message display
  • Clicking on coin buttons should deposit appropriate amount into soda machine.
  • Each coin deposited (It should increase the total amount deposited by the appropriate amount).
  • Clicking on a dollar bill to deposit one dollar into the machine.
  • Clicking dispense button without enough money deposited.
  • Clicking dispense button with enough money deposited should dispense a pop.
  • Clicking dispense button with more money that required to buy a pop should dispense pop and return any money over the amount required to buy pop.
  • Clicking a counterfeit coin and bill (They should be rejected and returned immediately).
  • Inserting money then pressing the coin return (total amount inserted should be returned).
  • Coins return by coin return (For example, 10 coins deposited should yield 10 coins returned).
  • Inserting one dollar and pressing dispense button with pop already in the dispenser – user should be prompted to remove pop from the dispenser before the machine dispenses another pop.
  • When the storage rack is empty – pressing the dispense button with appropriate amount of money inserted will not dispense a pop.
  • Inserted money when storage rack is empty (The money should be returned to user).
  • Entering more items than the storage rack can hold (User will be prompted that there are too many items).
  • Inserting one dollar and pressing the dispense button.
  • Clicking dispense button with no money inserted (user should be prompted for more money and no pop should be dispensed).
  • Generate a power surge of varying intensities and verify that the vending machine can handle it within specification.
  • Feed bills of all denominations and make product selections as quickly as possible and verify that soda is dispensed and the correct change is returned.
  • Feed change and make product selections as quickly as possible and verify that soda is dispensed and the correct change is returned.
  • Use a machine to press the buttons while periodically raising the pressure until failure and verify that their failure thresholds meet specification.
  • Use a machine to press the buttons with normal pressure but as rapidly as possible over several weeks and then place product in the machine and see if the buttons still function reliably.
  • Verify performance while tilting the vending machine, rocking the vending machine, and hitting the vending machine and verify it functions properly.