The Effectiveness of Regression Testing Techniques in Reducing the Occurrence of Residual Defects

Regression testing is a necessary maintenance activity that can ensure high quality of the modified software system, and a great deal of research on regression testing has been performed. Most of the studies performed to date, however, have evaluated regression testing techniques under the limited context, such as a short-term assessment, which do not fully account for system evolution or industrial circumstances. One important issue associated with a system lifetime view that we have overlooked in past years is the effects of residual defects -- defects that persist undetected -- across several releases of a system. Depending on an organization's business goals and the type of system being built, residual defects might affect the level of success of the software products. In this paper, we conducted an empirical study to investigate whether regression testing techniques are effective in reducing the occurrence and persistence of residual defects across a system's lifetime, in particular, considering test case prioritization techniques. Our results show that heuristics can be effective in reducing both the occurrence of residual defects and their age. Our results also indicate that residual defects and their age have a strong impact on the cost-benefits of test case prioritization techniques.