In an announcement made by Google, both of the company’s AMP and mobile-friendly test tools are now able to support the ability to edit and rerun the test, live. If you want to make any changes in the code editor to see how it’ll impact the AMP and/or mobile-friendly test, it’s possible to do it now.
Some good news to start your week! New feature in the Mobile Friendly and AMP Tests: they now support code editing
— Google Webmasters (@googlewmc) March 25, 2019
With this new feature, webmasters and developers can now quickly test changing of code in the testing tool, to find out if the results in the positive outcome in the test results. Now, you don’t have to make the change directly on your live web site and run the test after your code is deployed to see what the impact is on the test results.