@Override
 public void close() throws Exception {
   super.close();
   if (!openCalled) {
     Assert.fail("Open was not called before close.");
   }
   closeCalled = true;
 }
 @Override
 public void open(Configuration parameters) throws Exception {
   super.open(parameters);
   if (closeCalled) {
     Assert.fail("Close called before open.");
   }
   openCalled = true;
 }