code: def testPipelineIterator(self):
      strings = ["abcdefg", "helloworld!", "qwerty"]
      result = pipeline.load_pipeline(MockPipeline(), iter(strings))
  
      self.assertEqual(
          set(
              [MockStringProto(s + "_A") for s in strings]
              + [MockStringProto(s + "_B") for s in strings]
          ),
          set(result["dataset_1"]),
      )
      self.assertEqual(
          set(MockStringProto(s + "_C") for s in strings),
          set(result["dataset_2"]),
      )
  
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 5 for calling the PipelineTest obj's underlying member method code with example usage: obj.testPipelineIterator() without return types