Abstract. Conformance testing with the guaranteed fault coverage is based on distinguishing faulty system implementations from the corresponding system specification. We consider timed systems modeled by timed possibly nondeterministic finite state machines (TFSMs) and propose algorithms for distinguishing two TFSMs. In particular, we present a preset algorithm for separating two separable TFSMs and an adaptive algorithm for r-distinguishing two possibly non-separable TFSMs. The proposed techniques extend existing methods for untimed non-deterministic FSMs by dealing with the fact that unlike untimed FSMs in general, a TFSM has an infinite number of timed inputs. Correspondingly we state that the upper bounds on the length of distinguishing sequences are the same as for untimed FSMs.

The problem of constructing distinguishing experiments is a fundamental problem in the area of finite state machines (FSMs), especially for FSM-based testing. In this paper, the problem is studied for timed nondeterministic FSMs (TFSMs) with output delays. Given two TFSMs, we derive the TFSM intersection of these machines and show that the machines can be distinguished using an appropriate (untimed) FSM abstraction of the TFSM intersection. The FSM abstraction is derived by constructing appropriate partitions for the input and output time domains of the TFSM intersection. Using the obtained abstraction, a traditional FSM-based preset algorithm can be used for deriving a separating sequence for the given TFSMs if these machines are separable. Moreover, as sometimes two non-separable TFSMs can still be distinguished by an adaptive experiment, based on the FSM abstraction we present an algorithm for deriving an r-distinguishing TFSM that represents a corresponding adaptive experiment.

In this paper we consider a procedure of parallel composition construction of Timed Finite State Machines (TFSMs) using BALM-II and suggest different ways of getting linear functions that describe a set of output delays. Our research consists of three steps: at first step we consider composition of TFSMs when an output delay may be a natural number or zero; at secondwe add transitions under timeouts; at third we consider composition of TFSMs in general case (when output delays are described as sets of linear functions). This paper is devoted only to the first step of the research.

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Abstract. In this paper, we propose a fault model and a method for deriving complete test suites for nondeterministic FSMs with respect to the separability relation. Two FSMs are separable if there exists an input sequence such that the sets of output responses of these FSMs to the sequence do not intersect. In contrast to the well-known reduction and equivalence relations, the separability relation can be checked when the «all weather conditions» assumption does not hold for a nondeterministic Implementation Under Test (IUT). A (complete) test suite derived from the given (nondeterministic) FSM specification using the separability relation can detect every IUT that is separable from the given specification after applying each test case only once. Two algorithms are proposed for complete test derivation without the explicit enumeration of all possible implementations. The first algorithm can be applied when the set of possible implementations is the set of all complete nondeterministic submachines of a given mutation machine. The second algorithm is applied when the upper bound on the number of states of an IUT is known.