What are some strategies for testing large state machines?

Question

I inherited a large and fairly complex state machine. It has 31 possible states, all are really needed (big business process). It has the following inputs:

• Enum: C

Answer 1

Test based on the requirements. If a certain state is required to move to a certain other state whenever Completed is true, then write a test that automatically cycles through all the combinations of the other inputs (this should just be a couple for loops) to prove that the other inputs are correctly ignored. You should end up with one test for each transition arc, which I'd estimate would be somewhere on the order of 100 or 150 tests, not 4000.