code: def test_fit(self) -> None:
      dat = self.branin_experiment.lookup_data()
      with patch.object(
          self.sobol_model_spec, "fit", wraps=self.sobol_model_spec.fit
      ) as mock_model_spec_fit:
          self.sobol_generation_node.fit(
              experiment=self.branin_experiment,
              data=dat,
          )
      mock_model_spec_fit.assert_called_with(
          experiment=self.branin_experiment,
          data=dat,
          search_space=None,
          optimization_config=None,
      )
  
imports: import logging
  from logging import Logger
  from unittest.mock import patch, PropertyMock
  from ax.core.base_trial import TrialStatus
  from ax.core.observation import ObservationFeatures
  from ax.exceptions.core import UserInputError
  from ax.modelbridge.cross_validation import DiagnosticCriterion, MetricAggregation, SingleDiagnosticBestModelSelector
  from ax.modelbridge.factory import get_sobol
  from ax.modelbridge.generation_node import GenerationNode, GenerationStep
  from ax.modelbridge.model_spec import FactoryFunctionModelSpec, ModelSpec
  from ax.modelbridge.registry import Models
  from ax.modelbridge.transition_criterion import MaxTrials
  from ax.utils.common.logger import get_logger
  from ax.utils.common.testutils import TestCase
  from ax.utils.testing.core_stubs import get_branin_experiment
  from ax.utils.testing.mock import fast_botorch_optimize
label_desc: Use image node_id 3 for calling the TestGenerationNode obj's underlying member method code with example usage: obj.test_fit() without return types