Revalidation during the software maintenance phase

Software maintenance requires altering programs as a result of errors or changes in user requirements. However, during such modifications new errors may be introduced, causing unintended, adverse side effects in the software. Testing can prove to be expensive in terms of both human and computational resources. An examination is made of current selective retesting strategies which attempt to reduce such effort. Their advantages and limitations are described and a discussion is given of how these strategies could be extended and developed into a practical retesting tool allowing maintenance personnel to cope with large-scale revalidation procedures