@Test 
public void getDirectory() throws IOException
{

   HierarchicalDirectoryBuilder db=new HierarchicalDirectoryBuilder(tmp,3,5);
   File f = db.getDirectory ();
   Assert.assertTrue (f.exists ());
   String fileName = "file";
   f = db.getDirectory (fileName);
   File file = new File (f, fileName);
   file.createNewFile ();
   File f2 = db.getDirectory (fileName);
   Assert.assertNotEquals (f.getAbsolutePath (), f2.getAbsolutePath ());
}