As far as I know, __moduleRoot__ only comes into play when a module specifier appears in the configured import map. The original use case for import map support in jasmine-browser-runner was to load library code that lives outside the normal source directory, for example in node_modules.

My best guess from what you've told me is that you have modules in the src directory that are also listed in the import map. If that's the case, try removing them from the import map.

You are right. __moduleRoot__ is only used when "having an importmap".

I am importing with a id prefix (import { Control } from 'myPackageID/Controls.esm.js') because the path is not constant in all my scenarios. So I need to manipulate the path via an importMap in different runtime scenarios (and jasmine).

Thanks for the clarification.

I would have expected that module files from srcDir will get src and modules from specFiles/helpers will get spec.

I could create a PR with such a change, but wanted to have your OK or your opinion on this.
As this is an internal implementation detail (the prefix is added into sourcemap, too) I do not see a compatibility issue.

I think that makes sense.

The importMap property is provided by the user.
j-b-r does not know if it is meant to target files in srcDir or specDir.
We can not decide to 100% what folder is meant.

So my solution is to detect if a resulting path will be available in one of the path.
If it is not found it falls back to the existing __moduleRoot__. This can be projectBaseDir+moduleRootDir or projectBaseDir or current working directory.