Every time you pause or edit an Ad from within a single-adgroup test result screen, that specific test result will be archived automatically in an archive. This will allow you to see a historical record of all changes you made for each adgroup.
An archived 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 archived.
Only one test result per adgroup will be archived per day. If multiple changes are made to Ads within an adgroup in one day, the one archived test result will record all these changes in one place.
Archived test results are visible at the account, campaign or adgroup level as shown here: