Test sequence algorithms and formal languages

In conformance testing practice several test generation methods are based on the finite state machine specifications of protocols. These methods compose test suites by concatenating or merging test sequences like homing sequences, distinguishing sequences and unique input output sequences. This paper describes how notions from the conformance testing realm relate to formal languages. Different test sequences are expressed as operations on the finite state machine description itself The paper shows how a finite state machine description of a protocol can be transformed to a finite automation which accepts exactly the test sequences of the protocol. We present algorithms that compute that test sequence automata and we show that the computation of distinguishing sequences and unique input output sequences are NP-complete problems