Functional test generation for finite state machines

A functional test generation method for finite-state machines is described. A functional fault model, called the single-transition fault model, on the state transition level is used. In this model, a fault causes a single transition to a wrong destination state. A fault-collapsing technique for this fault model is also described. For each state transition, a small subset of states is selected as the faulty destination states so that the number of modeled faults for test generation is minimized. On the basis of this fault model, the authors developed an automatic test generation algorithm and built a test generation system. The effectiveness of this method is shown by experimental results on a set of benchmark finite-state machines. A 100% stuck-at fault coverage is achieved by the proposed method for several machines, and a very high coverage (>97%) is also obtained for other machines. In comparison with a gate-level test generator STG3, the test generation time is speeded up by a factor of 100.