code: def testRunPipelineSerial(self):
      strings = ["abcdefg", "helloworld!", "qwerty"]
      root_dir = self.create_tempdir().full_path
      pipeline.run_pipeline_serial(
          MockPipeline(), iter(strings), root_dir
      )
  
      dataset_1_dir = os.path.join(root_dir, "dataset_1.tfrecord")
      dataset_2_dir = os.path.join(root_dir, "dataset_2.tfrecord")
      self.assertTrue(tf.gfile.Exists(dataset_1_dir))
      self.assertTrue(tf.gfile.Exists(dataset_2_dir))
  
      dataset_1_reader = tf.python_io.tf_record_iterator(dataset_1_dir)
      self.assertEqual(
          set(
              [("serialized:%s_A" % s).encode("utf-8") for s in strings]
              + [
                  ("serialized:%s_B" % s).encode("utf-8")
                  for s in strings
              ]
          ),
          set(dataset_1_reader),
      )
  
      dataset_2_reader = tf.python_io.tf_record_iterator(dataset_2_dir)
      self.assertEqual(
          set(("serialized:%s_C" % s).encode("utf-8") for s in strings),
          set(dataset_2_reader),
      )
  
imports: import os
  from absl.testing import absltest
  from magenta.common import testing_lib
  from magenta.pipelines import pipeline
  from magenta.pipelines import statistics
  import tensorflow.compat.v1
label_desc: Use image node_id 4 for calling the PipelineTest obj's underlying member method code with example usage: obj.testRunPipelineSerial() without return types