A safe regression testing approach for safety critical systems

Regression testing is important activity during the software maintenance to deal with adverse effects of changes. Our approach is important for safety critical system as usually formal methods are preferred and highly recommended for the safety critical systems but they are also applied for the systems development of other than critical system. Our approach is based on Regression testing using VDM++ which takes two VDM++ specifications, one baseline and other delta (Changed) along with test suite for the baseline version. It compares both versions by using comparator module, identifies the change. By analyzing the change we classify the test cases from original test suite into obsolete, re-testable, and reusable test cases. Our scope is at unit level i.e. at class level. Our approach gets two versions of VDM++ specification and returns regression test suite for the delta version. Our approach distinguishes test cases which are still effective for the delta version of VDM++ specification and it differs from re-test all strategy as it can distinguish the test cases and identifies test cases which are useful for delta version. Test cases reusability and test case reduction is the main objective of our approach. Our approach presents how to perform regression testing using VDM++ specification during the maintenance of systems. (C) 2011 Elsevier Ltd. All rights reserved.