code: def test_pipeline(self):
      dataset = MockDataset()
      estimator0 = MockEstimator()
      transformer1 = MockTransformer()
      estimator2 = MockEstimator()
      transformer3 = MockTransformer()
      pipeline = Pipeline(
          stages=[estimator0, transformer1, estimator2, transformer3]
      )
      pipeline_model = pipeline.fit(
          dataset, {estimator0.fake: 0, transformer1.fake: 1}
      )
      model0, transformer1, model2, transformer3 = pipeline_model.stages
      self.assertEqual(0, model0.dataset_index)
      self.assertEqual(0, model0.getFake())
      self.assertEqual(1, transformer1.dataset_index)
      self.assertEqual(1, transformer1.getFake())
      self.assertEqual(2, dataset.index)
      self.assertIsNone(
          model2.dataset_index,
          "The last model shouldn't be called in fit.",
      )
      self.assertIsNone(
          transformer3.dataset_index,
          "The last transformer shouldn't be called in fit.",
      )
      dataset = pipeline_model.transform(dataset)
      self.assertEqual(2, model0.dataset_index)
      self.assertEqual(3, transformer1.dataset_index)
      self.assertEqual(4, model2.dataset_index)
      self.assertEqual(5, transformer3.dataset_index)
      self.assertEqual(6, dataset.index)
  
imports: import unittest
  from pyspark.ml.pipeline import Pipeline
  from pyspark.testing.mlutils import MockDataset, MockEstimator, MockTransformer, PySparkTestCase
label_desc: Use image node_id 1 for calling the PipelineTests obj's underlying member method code with example usage: obj.test_pipeline() without return types