[Meta] Automated testing of containers configuration within this repo

[sinedied]

I apologize in advance if it's not the right place to discuss this, but it's the best I could find.

After discovering recently an mismatch issue in a devcontainer definition (#1306), I was wondering how we could prevent this kind of issue happening again in the future?

Is there a CI task already existing where I could add testing on a specific image configuration to avoid regressions like this?
If not, do you think it would be possible to create it? I can prototype a PR.

What's your thoughts about this?

[Chuxel]

There's an internal CI job but it relies on closed source code at the moment. As devcontainers/spec#9 is completed we can move it into a better spot. That said, the way it works is that you can add a "test-project/test.sh" script to do more testing beyond building and starting the container(s) to verify contents.

Also congrats on getting issue 1337 - very leet. 😄