Software component testing : a standard and the effectiveness of techniques

This portfolio comprises two projects linked by the theme of software component testing, which is also often referred to as module or unit testing. One project covers its standardisation, while the other considers the analysis and evaluation of the application of selected testing techniques to an existing avionics system. The evaluation is based on empirical data obtained from fault reports relating to the avionics system. The standardisation project is based on the development of the BC BSI Software Component Testing Standard and the BCS/BSI Glossary of terms used in software testing, which are both included in the portfolio. The papers included for this project consider both those issues concerned with the adopted development process and the resolution of technical matters concerning the definition of the testing techniques and their associated measures. The test effectiveness project documents a retrospective analysis of an operational avionics system to determine the relative effectiveness of several software component testing techniques. The methodology differs from that used in other test effectiveness experiments in that it considers every possible set of inputs that are required to satisfy a testing technique rather than arbitrarily chosen values from within this set. The three papers present the experimental methodology used, intermediate results from a failure analysis of the studied system, and the test effectiveness results for ten testing techniques, definitions for which were taken from the BCS BSI Software Component Testing Standard. The creation of the two standards has filled a gap in both the national and international software testing standards arenas. Their production required an in-depth knowledge of software component testing techniques, the identification and use of a development process, and the negotiation of the standardisation process at a national level. The knowledge gained during this process has been disseminated by the author in the papers included as part of this portfolio. The investigation of test effectiveness has introduced a new methodology for determining the test effectiveness of software component testing techniques by means of a retrospective analysis and so provided a new set of data that can be added to the body of empirical data on software component testing effectiveness

Empirical Studies of Predicate-Based Software Testing

We report the results of three empirical studies of fault detection and stability performance of the predicate-based BOR (Boolean OperatoR) testing strategy. BOR testing is used to develop test cases based on formal software specification, or based on the implementation code. We evaluated the BOR strategy with respect to some other strategies by using Boolean expressions and actual software. We applied it to software specification cause-effect graphs of a safety-related real-time control system, and to a set of N-version programs. We found that BOR testing is very effective at detecting faults in predicates, and that BOR-based approach has consistently better fault detection performance than branch testing, thorough (but informal) functional testing, simple statebased testing, and random testing. Our results indicate that BOR test selection strategy is practical and effective for detection of faulty predicates, and is suitable for generation of safety-sensitive test-cases. 1. Introduct..