"Update" and "Save As New Version" options are available in different scenarios.
1). When a Test Case is created for the first time => Both the options Update, as well as Save as New Version would be available. (Update option will be available as long as TC is not associated with a Test Suite and Platform for Execution)
- A user may realize during the editing of the test case that both the old and the new version of the test case are valid separate test cases. To create a different version - he can "Save as a New Version".
- If he chooses to update his changes without creating a new version - he can "update"
2). When a Test Case has been written and is associated (linked) to a Test Suite and a platform for execution => only "Save as a New Version" option is available, and update option will not be shown.
- Changes to the same version (Update) is not allowed after the test case has been executed OR Linked to platform for execution.
- Any changes made henceforth would create a new Version ("Save as a New Version" is only allowed), because execution of a test case is done against a single version of a test case. This allows to track below easily -
- New versions/changes in Test Cases being created in the Project
- Which version of Test Case has been tested in the test suite (On Execution screen, see Version "V" Column)
A user may realize during the editing of the test case that both the old and the new version of the test case are valid separate test cases. The user may also create a test case and use it as a template to create new test cases without the bother of copying all the separate steps. This is particularly applicable for ad hoc and exploratory testers that may be recording test results against a generic test case and developing new test cases on the fly.