Assert known preconditions for test runs and fail early if unmet

📌 Limit trusted Composer plugins to a known list, allow user to add more Fixed is RTBC, not postponed: decreasing postponedness.
📌 Make build tests fail 1) more explicitly, 2) earlier when possible (failing StatusCheckEvent subscribers) Fixed landed: decreasing postponedness.

The only blockers left are 📌 Limit trusted Composer plugins to a known list, allow user to add more Fixed and 📌 Add symlink support to Composer Stager 2.0, require that version, and simplify UX & tests accordingly Fixed .

📌 Limit trusted Composer plugins to a known list, allow user to add more Fixed is in — that leaves only 📌 Add symlink support to Composer Stager 2.0, require that version, and simplify UX & tests accordingly Fixed .

I think thanks to the significant changes that have happened since November:

• no more use of vfs
• ComposerUtility is almost gone, in favor of relying on only composer commands (including in FixtureManipulator)
• the concept of "base requirements" was introduced a few days ago

… all that combined means that 📌 Assert status checks pass as early as possible in kernel and functional tests Closed: outdated now effectively will achieve the same as this I think!

But let's wait for that to land and then re-assess this.

If @tedbow agrees with #3337054-19: Assert status checks pass as early as possible in kernel and functional tests → , I think we can close this too.

#27 yep we are in much better place as far as testing now. child issues here fixed a lot of the problems

the only remaining issue here I see is the "Needs documentation updates" tag for COMPOSER_MIRROR_PATH_REPOS use.

Assigning to @phenaproxima to create the follow-up or anybody else wants to they could

I'd be fine with just repurposing this issue to avoid overhead.

Created follow-up 📌 Document why use COMPOSER_MIRROR_PATH_REPOS in build tests Active , So closing. Thanks for all the work on this issue, and the child issues

Automatically closed - issue fixed for 2 weeks with no activity.