Cost Optimizations in Runtime Testing and Diagnosis

Software testing and diagnosis (debugging) is a time-consuming but rather important task for improving software reliability. It is therefore necessary to devise an appropriate verification strategy that not only achieves this reliability goal, but also does this at a minimum cost. Since exhaustive testing is hardly ever possible, testing typically aims at detecting the presence of faults, by trying to produce a failure (the external manifestation of a fault). Once failures have been detected, the faults that produced them have to be localized. Unfortunately for developers, it has recently been shown that effective fault detection and effective fault localization are contradictory goals. In particular, it has been shown that focusing exclusively on fault detection has a detrimental effect on fault localization, canceling the savings in testing cost by an increase in diagnostic cost. In this thesis we explore the causes for this cost increase, and propose a shift in the goal of testing, focusing on techniques that achieve much better fault localization performance, while maintaining fault detection performance.Software TechnologyElectrical Engineering, Mathematics and Computer Scienc