Every time you pause or edit an Ad from within a single-adgroup test result screen, that specific test result will be saved automatically in an archive. This will allow you to see a historical record of all changes you made for each adgroup.
A saved test result for an adgroup will record any changes you make to the Ads within irrespective of whether the change was made from the automated or manual test result screen.
Only Ad changes made through the test result screen will result in the test result being saved. Ad changes made from any other screen will not cause the test result to be saved.
Only one test result per adgroup will be saved per day. If multiple changes are made to Ads within an adgroup in one day, the one saved test result will record all these changes in one place.
Saved test results are visible at the account, campaign or adgroup level as shown here: