Application of fuzzy expert system in test case selection for system regression test

Effective system test for consecutive releases of modern telecommunications system relies heavily on the selection of the test cases, because running all test cases in an existing test suite will consume an inordinate amount of time and money. Although many test selection techniques have been proposed on how to select test cases so that the number of test cases does not grow too large as the software evolves, to our knowledge they are all based on the assumption that the analysis of the source code is available. Very few studies have been made to explore the possibility of selecting test cases when the information of the source code is not available to testers. We present using fuzzy expert systems to solve the problem. The fuzzy expert system will resemble a human judgment via correlating knowledge that represents one or more of the following: customer profile, analysis of past test results, system failure rate, and wherever possible change in system architecture, to identify potentially critical test cases for system test. We piloted this fuzzy expert system in large telecommunication systems and the results showed that test effectiveness and efficiency was significantly improved.