@Test 
public void getDirectoryChange() throws IOException
{

   HierarchicalDirectoryBuilder db=new HierarchicalDirectoryBuilder(tmp,3,5);
   File f = db.getDirectory ();
   f = db.getDirectory ();
   for (int i = 0; i < 5; i++)
   {
      File file = new File (f, "file"+i);
      file.createNewFile ();
   }
   File f2 = db.getDirectory ();
   Assert.assertNotEquals (f.getAbsolutePath (), f2.getAbsolutePath ());
}