Input Output Symbolic Transition Systems Research Articles

A family of test selection criteria for Timed Input-Output Symbolic Transition System models

Test selection criteria can be applied to select, from a test suite, cost-effective subsets that are both cheaper to execute and as effective at detecting faults as the original suite. However, the choice of a test selection criterion is not straightforward for real-time systems, because most criteria presented in literature are for untimed systems and there is a lack of studies that investigate their cost-effectiveness when compared to specific criteria for real-time systems. In this paper, we investigate the cost-effectiveness of test selection criteria in test suite reduction for model-based testing of real-time systems, in particular for Timed Input-Output Symbolic Transition Systems (TIOSTS) models. First, we defined 18 test selection criteria for TIOSTS models and formalized a hierarchy of criteria partially ordered by strict inclusion. The defined criteria include transition-based criteria, data-flow-oriented criteria and real-time systems criteria. Second, we evaluated the cost-effectiveness of the criteria in an experiment. In the empirical study, we used a TIOSTS specification of a burglar alarm system, an implementation that simulated the system, and faults seeded into the implementation by using mutation testing. Results showed that, despite being a criterion for untimed systems, All-Transition-Pairs was the most cost-effective criterion for test case selection in model-based testing of real-time systems. We conclude that more cost-effective criteria that explore time-related features of models of real-time systems are still needed.

Conformance testing with ioco proxy-testers: application to web service compositions deployed in clouds

This paper describes a conformance testing method which aims at passively testing the conformance of component-based systems. This paper addresses the problem of reaction sequence observation in implementation environments where the installation of testing tools is not possible. The originality of the method resides in the definition of a proxy-tester model from a specification and in the reformulation of the ioco test relation with proxy-tester properties. Initially, we define the proxy-tester model and we give the theoretical background to automatically generate proxy-testers from specifications modelled with input-output symbolic transition system (IOSTS). The second part of this paper describes the application of this method on web service compositions deployed in Clouds. We provide algorithms and passive tester architectures to collect traces from several concurrent composition instances running in parallel. Finally, we present the testing tool Cloud Paste and experiment results on two Clouds, Google AppEngine and Windows Azure.

Using passive testing based on symbolic execution and slicing techniques: Application to the validation of communication protocols

This paper presents a new approach to perform passive testing based on the analysis of the control and data part of the system under test. Passive testing techniques are based on the observation and verification of properties on the behaviour of a system without interfering with its normal operation. Many passive testing techniques consider only the control part of the system and neglect data, or are confronted with an overwhelming amount of data values to process. In our approach, we consider control and data parts by integrating the concepts of symbolic execution and we improve trace analysis by introducing trace slicing techniques. Properties are described using Input–Output Symbolic Transition Systems (IOSTSs) and we illustrate in the paper how they can be tested on real execution traces optimizing the trace analysis. These properties can be designed to test the functional conformance of a protocol as well as security properties.In addition to the theoretical approach, we have developed a software tool that implements the algorithms presented in this paper. Finally, as a proof of concept of our approach and tool we have applied the techniques to a real-life case study: the SIP protocol. In particular, the proposed techniques are applied to a set of real execution traces extracted from an IMS/SIP architecture.