DevTools extensions not discovered when app entrypoint is under custom directory

[piotruela]

Sumary

DevTools extension discovery fails if the main isolate root library is under a custom test directory (patrol_test/ in our case) that is not recognized by DevTools’ package root heuristic. Extensions appear when tests are moved to integration_test/ which is a recognized root.

Context

I'm working on Patrol which has it's own devtools extension. We recently changed the default directory where all the tests are stored from integration_test to patrol_test. After doing so, we then found out that our devtools extension is not found when running tests.

Notes

DevTools root detection uses packageRootFromFileUriString, which only recognizes lib, bin, integration_test, test, benchmark, example as valid top‑level dirs. Custom test dirs like patrol_test/ are not recognized, so the root resolves incorrectly and package_config.json lookup fails.

Would it be possible to make it more configurable so that we could point to patrol_test directory in our case?