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.

In the paper, the non separability relation for finite state machines with time outs is studied. A specific feature of such machines is integer valued delays, or time outs, which determine how long the finite state machine will stay in one or another state if there are no input actions. If the time out is over and no input symbol has been applied, then the TFSM state is changed according to the transition under time delay. In the paper, an algorithm for constructing a separating sequence for such finite state machines is pre sented. Here, the separating sequence is a timed input sequence for which sets of input sequences of the TFSM do not intersect; hence, it is sufficient to apply the separating sequence once in order to distinguish the TFSMs by their output reactions. This algorithm underlies the algorithm for construction of test suites with respect to non separability relation in the case where the fault domain is specified by means of a muta tion machine. Test suite derivation with respect to non separability relation by way of "TFSM to FSM" trans formation is discussed.

Abstract-In this paper we consider one of the classical finite state machine (FSM) model modifications -FSM with time-outs (or timed FSM). In this model in addition to the ordinary transitions under inputs there are transitions under time-outs when no input is applying. The behavior of many modern systems includes time-outs, for example, mobile phones, etc. In the past few years some work have been carried out on studying different relations between timed FSMs. Non-separability relation is very attractive for non-deterministic classical FSMs and FSMs with time-outs course for this relation we don't need «all weather conditions» while testing. In this paper we present and compare two approaches for building a separating sequence for two separable FSMs with time-outs. One of them is using a conversion to classical FSMs, while another one is dealing directly with timed FSMs.

In this paper we describe software tool «FSMTest-1.0» that was developed by group of authors from the department of Computer science of Tomsk State University. The tool contains implementations of wellknown and original test suites generation methods for different models with finite numbers of transitions. The main contribution of our tool is that it derives test suites with the guaranteed fault coverage.