No I was sharing an example of a framework that does include "a testing system that allows it to inject mouse events".

That being said mouse events and similar isn't hard to do, e.g. start with a fixed resolution (using xrandr) then xdotool or similar. Ideally if the application has accessibility feature it won't be as finicky.

My point though was just to show that testing with GUI is not infeasible.

Apparently there is even a "UI Testing for devs & agents" https://www.chromatic.com which I found via Visual TDD https://www.chromatic.com/blog/visual-test-driven-developmen... I can't recommend this but it does show even though the person I was replying with can't use Puppeteer in their context the tooling does exist and the principles would still apply.