Software code is tested to determine relative performance of the software code. Successfully executing a test may be used to flag problems in a code repository to be corrected or criteria for accepting code for acceptance to the repository. To further evaluate test results, the test may be run several times on the same code version to determine a test result stability score describing how the test results may vary in different executions, such as a frequency that the code passes the test. Based on the score, additional tests may be run to further refine test result stability score. To evaluate time-variance of testing, when a code version fails a test, a previous version of the code may be run with the same test and the results compared to determine if a new regression was introduced.