code: def test_failure(self) -> None:
      self.assertFalse(PathManager.exists("test://foo"))
      PathManager.register_handler(TestPathHandler())
      # make sure that TestPathHandler is being used
      self.assertTrue(PathManager.exists("test://foo"))
  
      checkpoint_folder = "test://root"
  
      checkpoint_hook = CheckpointHook(
          checkpoint_folder, {}, phase_types=["train"]
      )
      config = get_test_task_config()
      task = build_task(config)
      task.prepare()
  
      # we should raise an exception while trying to save the checkpoint
      with self.assertRaises(TestException):
          checkpoint_hook.on_phase_end(task)
  
imports: import copy
  import importlib
  import os
  import shutil
  import tempfile
  import torch
  from classy_vision.generic.util import load_checkpoint
  from classy_vision.hooks import CheckpointHook
  from classy_vision.tasks import build_task
  from classy_vision.trainer import LocalTrainer
  from fvcore.common import file_io
  from fvcore.common.file_io import PathHandler, PathManager
  from test.generic.config_utils import get_fast_test_task_config, get_test_task_config
  from test.generic.hook_test_utils import HookTestBase
label_desc: Use image node_id 4 for calling the TestCheckpointHook obj's underlying member method code with example usage: obj.test_failure() without return types