The purpose of this project is to assess and improve the quality (efficiency and completeness) of current regression tests. It includes the following activities: * Automatic test selection in a Build Bot (see SelectiveTestBuildBot) * Selective testing in the Early Warning System (see SelectiveTestEWS) * Extension with top-100 websites using automatic invariant analysis (see Top100Invariant) * Research on isolation of flaky tests and further research topics (RegressionTestResearch) The work is currently being performed by the Department of Software Engineering of the University of Szeged (see [wiki:"Companies and Organizations that have contributed to WebKit"]).