Issue

• sub-tests are invoked independently, thus runtime.Callers can't access the info of the root test
• os.Getwd() can be used, to get the current directory of a test. However, that dir might be changed using t.Chdir(..). If Chdir was called that can not be detected on t.

Solution

• don't support the persistent test fetcher in sub tests :/
• store state data in the module root in a single dir for all packages