Application of system models in regression test suite prioritization

During regression testing, a modified system needs to be retested using the existing test suite. Since test suites may be very large, developers are interested in detecting faults in the system as early as possible. Test prioritization orders test cases for execution to increase potentially the chances of early fault detection during retesting. Most of the existing test prioritization methods are based on the code of the system, but model-based test prioritization has been recently proposed. System modeling is a widely used technique to model state-based systems. The existing model based test prioritization methods can only be used when models are modified during system maintenance. In this paper, we present model-based prioritization for a class of modifications for which models are not modified (only the source code is modified). After identification of elements of the model related to source-code modifications, information collected during execution of a model is used to prioritize tests for execution. In this paper, we discuss several model-based test prioritization heuristics. The major motivation to develop these heuristics was simplicity and effectiveness in early fault detection. We have conducted an experimental study in which we compared model-based test prioritization heuristics. The results of the study suggest that system models may improve the effectiveness of test prioritization with respect to early fault detection.