Regression test selection for Java software

Regression testing is applied to modified software to provide confidence th at the changed parts behave as intended and that the unchanged parts have n ot been adversely affected by the modifications. To reduce the cost of regr ession testing, test cases are selected from the test suite that was used t o test the original version of the software this process is called regressi on test selection. A safe regression-test-selection algorithm selects every test case in the test suite that may reveal a fault in the modified softwa re. Safe regression-test-selection techniques can help to reduce the time r equired to perform regression testing because they select only a portion of the test suite for use in the testing but guarantee that the faults reveal ed by this subset will be the same as those revealed by running the entire test suite. This paper presents the first safe regression-test-selection te chnique that, based on the use of a suitable representation, handles the fe atures of the Java language. Unlike other safe regression test selection te chniques, the presented technique also handles incomplete programs. The tec hnique can thus be safely applied in the (very common) case of Java softwar e that uses external libraries or components; the analysis of the external code is not required for the technique to select test cases for such softwa re. The paper also describes RETEST, a regression-test-selection system tha t implements our technique, and a set of empirical studies that demonstrate that the regression-test-selection algorithm can be effective in reducing the size of the test suite.