In #2121 and later #2384 we added the necessary changes to have proper JS unit tests. The biggest PR there, #2176, introduced the necessary infrastructure leveraging @wordpress/scripts for this.

That package not only provides utilities for unit tests, but also some functionality for E2E tests. Most of the needed functionality for that has been added to our plugin already.

In order to catch regressions and test more complex UI flows, it would be great to build upon this infrastructure and actually write E2E tests for the AMP Stories editor and run them on Travis CI.

We could also use E2E tests for other areas:

• Verify whether AMP specific features in the block editor are available, depending on the plugin settings.
• Verify that plugin settings change depending on selected experiences.
• Verify that customizer settings are available.
  This specifically was something that was only caught last minute before the 1.2 release, which makes it an ideal thing to check for in E2E tests.