Abstracts Computer Science

Regression testing experiments

by Kent Sayre

Software maintenance is an expensive part of the software lifecycle: estimates put its cost at up to two-thirds of the entire cost of software. Regression testing, which tests software after it has been modified to help assess and increase its reliability, is responsible for a large part of this cost. Thus, making regression testing more efficient and effective is worthwhile. This thesis performs two experiments with regression testing techniques. The first experiment involves two regression test selection techniques, Dejavu and Pythia. These techniques select a subset of tests from the original test suite to be rerun instead of the entire original test suite in an attempt to save valuable testing time. The experiment investigates the cost and benefit tradeoffs between these techniques. The data indicate that Dejavu can occasionally select smaller test suites than Pythia while Pythia often is more efficient at figuring out which test cases to select than Dejavu. The second experiment involves the investigation of program spectra as a tool to enhance regression testing. Program spectra characterize a program's behavior. The experiment investigates the applicability of program spectra to the detection of faults in modified software. The data indicate that certain types of spectra identify faults on a consistent basis. The data also reveal cost-benefit tradeoffs among spectra types.