code: def test_after_test_iter(self):
      timestamp = time.strftime("%Y%m%d_%H%M%S", time.localtime())
      TextDetLocalVisualizer.get_instance(
          "visualizer_test",
          vis_backends=[dict(type="LocalVisBackend", img_save_dir="")],
          save_dir=timestamp,
      )
      runner = Mock()
      runner.iter = 1
  
      hook = VisualizationHook(enable=False)
      hook.after_test_iter(runner, 1, self.data_batch, self.outputs)
      self.assertFalse(osp.exists(timestamp))
  
      hook = VisualizationHook(enable=True)
      hook.after_test_iter(runner, 1, self.data_batch, self.outputs)
      self.assertTrue(osp.exists(timestamp))
      shutil.rmtree(timestamp)
  
file_path: mmocr/tests/test_engine/test_hooks/test_visualization_hook.py
imports: import os.path
  import shutil
  import time
  from unittest import TestCase
  from unittest.mock import Mock
  import torch
  from mmengine.structures import InstanceData
  from mmocr.engine.hooks import VisualizationHook
  from mmocr.structures import TextDetDataSample
  from mmocr.visualization import TextDetLocalVisualizer
label_desc: Use image node_id 3 for calling the TestVisualizationHook obj's underlying member method code with example usage: obj.test_after_test_iter() without return types