unit-tests should work with default intellj import

On branch 4.5.x (maybe on master, too, must be checked) lots of test are failing when runned with intelliJ.
This happens when the sub-projects of main are imported alltogether with the paren-pom of the main project (which is the usual case).
For an overview of the not working tests see screenshot.

There is a "workaround" to set the working directory for the test explicitely. (see screenshot). Or. alternatively, the sub-project which contains the test can be imported "stand-alone".
But ususally developers rely on that a test just cen be run after having checked it out from git without any speclai settings.

So. All the unit test must work with "usual" project-imports without any IDE-settings for the test.