code: def test_lcbc012_long_callback_ctx(dash_duo, manager):
      with setup_long_callback_app(manager, "app_callback_ctx") as app:
          dash_duo.start_server(app)
          dash_duo.find_element("button:nth-child(1)").click()
          dash_duo.wait_for_text_to_equal("#running", "off")
  
          output = json.loads(dash_duo.find_element("#result").text)
  
          assert output["triggered"]["index"] == 0
  
imports: import json
  import sys
  import pytest
  from tests.integration.long_callback.utils import setup_long_callback_app
label_desc: Use image node_id 1 for calling a global function with example usage: test_lcbc012_long_callback_ctx(dash_duo, manager) without return types