AbstractSoftware revalidation through retesting during the maintenance phase is essential for establishing confidence in the reliability of the modified programs. In this paper, we present a testing criterion and techniques for revalidating modified programs as well as the conditions to determine the necessity for revalidation of the modified program. By comparing programs and identifying the textual and semantic changes between them, it is shown that the number of test cases to be rerun can be reduced compared to the current revalidation methods. Our method is applicable to programs with different control structures from the original program with a little effort by treating the test case reuse problem as a constraint satisfaction problem. In addition, application of an zero‐one integer programming model to select the minimal set of paths to be retested is explore