Write to disk in Platform based JUnit tests

I am using createData(). But with the other parameter set
Here some code parts which I use:


Code:

FileObject fo = FileUtil.getConfigRoot().createData(FILENAME, EXTENSION);
      lock = fo.lock();
      try (PrintWriter to = new PrintWriter(fo.getOutputStream(lock))) {
        to.println("some stuff");
        to.flush();
      } finally {
        lock.releaseLock();
      }




This creates the file an later I need to get the URL but as "file://"


Code:

FileObject fo = FileUtil.getConfigRoot().getFileObject(FILENAME, EXTENSION); //this work
URI uri = Utilities.toURI(FileUtil.toFile(fo)).toString(); //this will be processed by external code than - it Fails as toFile(..) creates null




We are using ant for building which should not be any difference to the code itself.