You are on the right track.
The next steps depend on exactly what you are trying to do. For a test I just created TestGeneious.initializeAllPlugins() was enough to use createNewNoteType and getNoteType.
Note that you need to call DocumentNoteUtilities.setNoteType before using getNoteType to retrieve a newly created note type.
If that still isn't working because the local database is not set up then add the following to your test:
I hope that helps.