Abstract: Provided are techniques for improving a test suite. A list of tests in a test suite is created, sorted in order of increasing run time, wherein multiple tests having a same run time are sorted in order of decreasing code block coverage. For each test on the list, it is determined whether the test covers one or more code blocks not already covered by at least one previously processed test. In response to determining that the test does cover one or more code blocks not already covered by the at least one previously processed test, the test is added to an optimized test suite. The optimized test suite is stored.