Hybrid methods for reducing database schema test suites: experimental insights from computational and human studies

Given that a relational database is a critical component of many software applications, it is important to thoroughly test the integrity constraints of a database's schema, because they protect the data. Although automated test data generation techniques ameliorate the otherwise manual task of database schema testing, they often create test suites that contain many, sometimes redundant, tests. Since prior work presented a hybridized test suite reduction technique, called STICCER, that beneficially combined Greedy test suite reduction with a test merging method customized for database schemas, this paper experimentally evaluates a different hybridization. Motivated by prior results showing that test suite reduction with the Harrold-Gupta-Soffa (HGS) method can be more effective than Greedy at reducing database schema test suites, this paper evaluates an HGS-driven STICCER variant with both a computational and a human study. Using 34 database schemas and tests created by two test data generators, the results from the computational study reveal that, while STICCER is equally efficient and effective when combined with either Greedy or HGS, it is always better than the isolated use of either Greedy or HGS. Involving 27 participants, the human study shows that, when compared to test suites reduced by HGS, those reduced by a STICCER-HGS hybrid allow humans to inspect test cases faster, but not always more accurately.