code: def testPipelineWarnMissingNode(self):
      channel_one = types.Channel(type=_ArtifactTypeOne)
      channel_two = types.Channel(type=_ArtifactTypeTwo)
      component_a = _make_fake_component_instance(
          "component_a", _OutputTypeA, {"a": channel_one}, {}
      )
      component_b = _make_fake_component_instance(
          name="component_b",
          output_type=_OutputTypeB,
          inputs={"a": component_a.outputs["output"]},
          outputs={"b": channel_two},
      )
  
      warn_text = (
          "Node component_b depends on the output of node component_a, "
          "but component_a is not included in the components of pipeline. "
          "Did you forget to add it?"
      )
      with self.assertWarnsRegex(UserWarning, warn_text):
          pipeline.Pipeline(
              pipeline_name="name",
              pipeline_root="root",
              components=[
                  component_b,
              ],
              metadata_connection_config=self._metadata_connection_config,
          )
  
imports: import itertools
  import os
  from typing import Any, Dict, Optional, Type
  import tensorflow
  from tfx import types
  from tfx.dsl.components.base import base_beam_component
  from tfx.dsl.components.base import base_component
  from tfx.dsl.components.base import base_executor
  from tfx.dsl.components.base import base_node
  from tfx.dsl.components.base import executor_spec
  from tfx.dsl.placeholder import placeholder
  from tfx.orchestration import metadata
  from tfx.orchestration import pipeline
  from tfx.types.component_spec import ChannelParameter
  from tfx.types.component_spec import ExecutionParameter
  from tfx.utils import test_case_utils
label_desc: Use image node_id 6 for calling the PipelineTest obj's underlying member method code with example usage: obj.testPipelineWarnMissingNode() without return types