code: def test_add_model_checkpoint_callback(self, mock_super_tuner):
      remote_tuner = self._remote_tuner(None, None, self._study_config)
      callbacks = []
      trial_id = "test_trial_id"
      remote_tuner._add_model_checkpoint_callback(callbacks, trial_id)
      self.assertLen(callbacks, 1)
      self.assertEqual(
          callbacks[0].filepath,
          os.path.join(remote_tuner.directory, trial_id, "checkpoint"),
      )
  
imports: import os
  import time
  from keras_tuner.engine import hypermodel
  from keras_tuner.engine import hyperparameters
  from keras_tuner.engine import oracle
  from keras_tuner.engine import trial
  from keras_tuner.engine import tuner
  import mock
  import tensorflow
  from tensorboard.plugins.hparams import api
  from tensorflow_cloud.core import deploy
  from tensorflow_cloud.core import machine_config
  from tensorflow_cloud.core import validate
  from tensorflow_cloud.tuner import cloud_fit_client
  from tensorflow_cloud.tuner import tuner
  from tensorflow_cloud.tuner.tuner import vizier_client
  from tensorflow_cloud.utils import google_api_client
  from tensorflow_cloud.utils import tf_utils
label_desc: Use image node_id 27 for calling the CloudTunerTest obj's underlying member method code with example usage: obj.test_add_model_checkpoint_callback(mock_super_tuner) without return types