build fails when rootURL='' as default and rootURL set to '/' for test environment

[void-mAlex]

Environment: development
cleaning up...
Build Error (WaitForTrees)

Could not find app javascript: "/assets/my-app.js" in tests/index.html. Found the following instead:
 - /testem.js
 - /assets/vendor.js
 - /assets/test-support.js
 - /assets/my-app.js
 - /assets/tests.js
 -

For more information about this error: https://github.com/thoov/stitch/wiki/Could-not-find-asset-in-entry-file-e
rror-help

the use case for relative url is when you need a build that can be deployed in any path relative to the server (note locationType has to be hash/none for the router to work in this config).
eg path:
https://example.com/app/ <--web app
https://localhost/ <-- wrapped hybrid app cordova/capacitor

currently this setup works in the classic build pipeline (though not sure if it's supported)

issues is that rootURL = '/' is required due to the setup of the testing pipeline and files. I have found no combination of rootURL that would make both /tests and ember test command with at the same time with embroider and allow a relative path
tried ../ /../ ./ in various combos between the different environments (dev / test)

it is theoretically possible to do two builds for this managing the rootURL by way of some env flag but that would be a major drawback for DX and overhead on the developer and CI resources

and now for what I've found is that

embroider/packages/compat/src/v1-app.ts

Line 666 in 3b0dd91

let rootURL = this.config.readConfig().rootURL;

always returns the development environment rootURL value even when receiving the tests/index.html values to check which are correctly prefixed with a different url

not sure what the fix is here but I guess this would work better if it read the correct config for the correct html file

[void-mAlex]

closing as fix has been merged and released