code: def test_render_template(dag_maker):
      with dag_maker(
          "test_druid_render_template",
          default_args={"start_date": DEFAULT_DATE},
      ):
          operator = DruidOperator(
              task_id="spark_submit_job",
              json_index_file=JSON_INDEX_STR,
              params={
                  "index_type": "index_hadoop",
                  "datasource": "datasource_prd",
              },
          )
  
      dag_maker.create_dagrun(
          run_type=DagRunType.SCHEDULED
      ).task_instances[0].render_templates()
      assert RENDERED_INDEX == json.loads(operator.json_index_file)
  
file_path: airflow/tests/providers/apache/druid/operators/test_druid.py
imports: from __future__ import annotations
  import json
  from unittest.mock import MagicMock, patch
  import pytest
  from airflow.providers.apache.druid.hooks.druid import IngestionType
  from airflow.providers.apache.druid.operators.druid import DruidOperator
  from airflow.utils import timezone
  from airflow.utils.types import DagRunType
label_desc: Use image node_id 1 for calling a global function with example usage: test_render_template(dag_maker) without return types