State Transition Diagram Exercise
Rex Black · 2016
This chapter examines a series of exercises related to state testing by creating a state transition diagram for the Omninet kiosks and building test cases to cover that diagram. The public Internet access kiosks can be in various states based on receipt of payment and active sessions. The basic difference between covering the diagram and covering the table is that the table takes into account the “can't happen” and “shouldn't happen” situations. Where extensive testing or considerable error handling and robustness tests are required, then users should plan to cover the table. One can discover memory exhaustion problems, intermittent lock-ups and crashes, and other such bugs with such tests. The ATM will validate the customer's PIN, then allow a withdrawal. It dispenses the cash and returns the customer's card all at once at the end of the transaction. The customer can cancel instead of entering the PIN or a withdrawal request. The account should have an available balance small enough that it is possible to make a withdrawal request that exceeds the available balance.