An incremental approach to unit testing during maintenance

An incremental testing system to aid in unit testing during the maintenance stage is described. Based on data-flow testing, the system is designed for use in a programming environment; it shares common information and techniques with tools typically found in programming environments. In response to a change in a module, the incremental tester reuses the analysis and test cases from the previous testing session. The analysis is incrementally updated to determine areas of the program that must be retested. From the updates, the tester determines which test cases must be rerun, which may be eliminated, and whether the test cases are sufficient for the changed program