code: def test_encode_bcl_component_pre_output(self):
      pre_output = hooks.BCLComponentPreOutput(
          vars={"var_key": "var_value"},
      )
      self.assertProtoEquals(
          pre_output.encode(),
          json_format.ParseDict(
              {"vars": {"var_key": {"string_value": "var_value"}}},
              execution_hook_pb2.PreExecutionOutput(),
          ),
      )
  
file_path: tfx/tfx/dsl/hooks_test.py
imports: import tensorflow
  from tfx.dsl import hooks
  from tfx.proto.orchestration import execution_hook_pb2
  from google.protobuf import json_format
label_desc: Use image node_id 2 for calling the HooksTest obj's underlying member method code with example usage: obj.test_encode_bcl_component_pre_output() without return types