Test sequence generation and timed testing

Recent developments on formal specification based protocol test generation techniques are presented. A new technique is introduced that is based on well-known program slicing method. It is shown that using a test suite structure as the slicing criteria, LOTOS specifications can be sliced, and the slicing can be continued until the behaviour of a single test case is obtained. Test sequence generation from the sliced specifications are explained with small examples. Next discussed is the timed testing with an emphasis on stream-based systems such as multimedia systems. Timed extensions of two basic models are presented. A model of automata extended with time is shown to be useful for protocols which exhibit time-dependent behaviour. A more general model is the real-time extension of LOTOS. A simple multimedia system is defined using ET-LOTOS. It is shown that test sequence generation for stream-based systems requires new approaches as well as new languages for specifying the test cases.