On Minimizing Regression-Suites using On-Line Set-Cover

This paper is about the experience gained in IBM Haifa Research Lab (HRL) in creating regression-suites and minimizing their size, while maintaining high quality as measured by coverage. The problem that we solve, while similar to the one addressed in the literature, has a key difference; the compaction algorithm has to be implemented on-line due to the large number of tests processed. We compare strategies for implementing on-line set-cover. The trade-offs are between quality of solution (as expressed by the size of the test suite), memory and CPU. We show that on-line compaction strategies, on our data, are almost as good as keeping all the tests and then compacting off-line.