An Evaluation of Change-Based Coverage Criteria

Various coverage criteria are commonly used to assess the quality of test suites, but achieving full coverage according to these criteria is often impossible or impractical. Our research starts from the popular assumption that a disproportionate number of faults is likely to reside in recently changed code. Based on this assumption, we propose several change-based coverage criteria that reflect to what extent changes with respect to a previous program version are exercised by a test suite. In a set of experiments on programs from the SIR repository, we found change-based criteria to reveal faults better than traditional criteria, and to enable the construction of much smaller test suites with similar fault detection effectiveness. We also report on a case study that shows that achieving (near) 100% coverage according to a change-based criterion is both feasible and useful.