code: def test_allowed_message_origins(self):
      response = self.fetch("/_stcore/host-config")
      response_body = json.loads(response.body)
      self.assertEqual(200, response.code)
      self.assertEqual(
          {
              "allowedOrigins": _DEFAULT_ALLOWED_MESSAGE_ORIGINS,
              "useExternalAuthToken": False,
              # Default host configuration settings:
              "enableCustomParentMessages": False,
          },
          response_body,
      )
      # Check that localhost NOT appended/allowed outside dev mode
      self.assertNotIn(
          "http://localhost",
          response_body["allowedOrigins"],
      )
  
imports: import json
  import os
  import tempfile
  from unittest.mock import MagicMock
  import tornado.httpserver
  import tornado.testing
  import tornado.web
  import tornado.websocket
  from streamlit.runtime.forward_msg_cache import ForwardMsgCache, populate_hash_if_needed
  from streamlit.runtime.runtime_util import serialize_forward_msg
  from streamlit.web.server.routes import _DEFAULT_ALLOWED_MESSAGE_ORIGINS
  from streamlit.web.server.server import HEALTH_ENDPOINT, HOST_CONFIG_ENDPOINT, MESSAGE_ENDPOINT, HealthHandler, HostConfigHandler, MessageCacheHandler, StaticFileHandler
  from tests.streamlit.message_mocks import create_dataframe_msg
  from tests.testutil import patch_config_options
label_desc: Use image node_id 3 for calling the HostConfigHandlerTest obj's underlying member method code with example usage: obj.test_allowed_message_origins() without return types