Deriving Distinguishing Sequences for Input/Output Automata
Nina Vladimirovna Yevtushenko, Igor Borisovich Burdonov, Alexandr Kossachev · 2020
Input/Output (I/O) automata are widely used when deriving high quality tests for (components of) complex discrete systems based on so called distinguishing sequences. For I/O automata, the number of distinguishability relations is much bigger than for classical deterministic Finite State Machines (FSM). In order to avoid submitting the same test sequence several number of times, i.e., avoid the "all weather conditions" assumption, the separability relation can be considered. If two Input/Output automata are separable then there exists an input sequence such that after submitting this sequence and observing produced outputs it can be uniquely concluded which automaton is under testing. In this paper, we modify the discipline of applying input sequences and discuss the derivation of separating sequences for automata with mixed states, i.e., states where transitions both under inputs and under outputs are defined, as well as with cycles labeled by outputs. We also illustrate how an adaptive separating sequence can be derived when both automata are input-enabled.