The Test Script or Test Case library in Enterprise Tester is a central project repository that stores all Test Scripts / Test Cases for a project.
Test Scripts can be grouped as required, for example by release, iteration or system.
Once Test Scripts are established these can be re-used and adjusted as required, with no need to recreate them for future releases.
Changes made to an existing Test Script will automatically update the related Test Execution information unless the Test is in the middle of being executed.