code: def test_failed(self) -> None:
      fail_reason = "testing"
      self.trial.runner = SyntheticRunner()
      self.trial.run()
      self.trial.mark_failed(reason=fail_reason)
  
      self.assertTrue(self.trial.status.is_failed)
      self.assertTrue(self.trial.did_not_complete)
      self.assertEqual(self.trial.failed_reason, fail_reason)
  
imports: import itertools
  from copy import deepcopy
  from unittest import mock
  from unittest.mock import Mock, patch
  import pandas
  from ax.core.base_trial import BaseTrial, TrialStatus
  from ax.core.data import Data
  from ax.core.generator_run import GeneratorRun, GeneratorRunType
  from ax.core.runner import Runner
  from ax.exceptions.core import UserInputError
  from ax.runners.synthetic import SyntheticRunner
  from ax.utils.common.result import Ok
  from ax.utils.common.testutils import TestCase
  from ax.utils.testing.core_stubs import get_arms, get_branin_arms, get_experiment, get_objective, get_test_map_data_experiment
label_desc: Use image node_id 8 for calling the TrialTest obj's underlying member method code with example usage: obj.test_failed() without return types