Generation of complete test suites from mealy input/output transition systems

Abstract

Model-based testing overcomes challenges in software testing by generating automated test cases from behavior models, e.g. finite state machine (FSM) and input/output transition system (IOTS). Despite the existence of methods for IOTSs, the problem of selection of test cases is an important and difficult topic. The current methods from IOTSs do not provide the same support offered by the existing theory for FSMs, as complete fault coverage. In this paper, we propose a test generation method for IOTSs based on the W method developed for FSMs. The basic idea is to generate a transition cover set and a characterization set and concatenate them to generate complete test suites for IOTSs in a bounded number of steps. The method generates test suites with complete fault coverage for a given fault domain and is targeted at a class of IOTSs, called mealy IOTS, which accepts inputs only in stable states. Results from a case study show the proposed algorithm can achieve better results than a classical method for IOTSs.

Complete IOCO test cases: a case study

“…The test suite generated by the algorithm detects all faults in the fault domain. A case study, presented in [13] illustrated the feasibility of the method. However, more empirical studies with real specifications are needed to evaluate and measure the efficiency of this testing method.…”

“…Mealy IOTSs [16,13] behave similarly to deterministic Mealy machines in that they only receive inputs in quiescent states. This is an important class of IOTSs because several results from IOTS-and FSM-based testing theories, such as the use of fault domains, converge on this class of IOTSs.…”

“…Paiva and Simao [13] proposed a reformulation of the Wmethod for FSMs [5] to IOTSs; their method aims at generating complete test suites with complete fault coverage for a given fault domain and is targeted at the class of Mealy IOTS. Adopting this class of IOTSs as test models implies that one can avoid the distortion caused by asynchronous channels in testing, since in Mealy IOTSs an input is provided only if all outputs have been observed and quiescence is reached (i.e., all communication channels are known to be empty).…”

“…In [13], the W-method from FSMs [5] has been adapted for a class of IOTSs, named Mealy IOTSs [13]. This class requires quiescence (i.e., absence of outputs) to be reached before the inputs are provided; therefore, problems related to the communication between testers and implementations can be eliminated.…”

“…The aim of this paper is to measure the efficiency of Complete IOCO [13], an offline and deterministic test generation method, in comparison with the nondeterministic and online method of IOCO [17] as implemented in the JTorX tool [1]. To this end, we use the well-known ETCS Ceiling Speed Monitor benchmark from the railway domain [3,2], as well as the Body Comfort System [11] and the Turn Indicator Lights [14] from the automotive domain.…”