Do not run this built-in script in a production instance. It can result in irretrievable data loss.
Use Test Runner to run JUnit and Spock tests, for use in a development instance only. Follow these steps to run the built-in script:
Enter the list of packages to scan for tests in Packages.
Enter tests to run in Tests.
You can select Preview instead of Run to view changes before implementing them.
Once you select Run, the Results of the script appear.