code: def test_threaded_server_smoke(dash_thread_server):
      app = dash.Dash(__name__)
  
      app.layout = html.Div(
          [
              html.Button("click me", id="clicker"),
              html.Div(id="output", children="hello thread"),
          ]
      )
      dash_thread_server(
          app, debug=True, use_reloader=False, use_debugger=True
      )
      r = requests.get(dash_thread_server.url)
      assert r.status_code == 200, "the threaded server is reachable"
      assert (
          'id="react-entry-point"' in r.text
      ), "the entrypoint is present"
  
file_path: dash/tests/unit/test_app_runners.py
imports: import os
  import sys
  import requests
  import pytest
  import dash
  from dash import html
label_desc: Use image node_id 1 for calling a global function with example usage: test_threaded_server_smoke(dash_thread_server) without return types