code: def test_auth_provider() -> None:
      bt = bst.BokehTornado(applications={})
      assert isinstance(bt.auth_provider, NullAuth)
  
      class FakeAuth:
          get_user = "get_user"
          endpoints = []
  
      bt = bst.BokehTornado(applications={}, auth_provider=FakeAuth)
      assert bt.auth_provider is FakeAuth
  
imports: from __future__ import annotations
  import pytest
  import json
  import logging
  from _util_server import http_get, url
  from tornado.web import StaticFileHandler
  from bokeh.application import Application
  from bokeh.client import pull_session
  from bokeh.core.types import ID
  from bokeh.server.auth_provider import NullAuth
  from bokeh.server.views.static_handler import StaticHandler
  from bokeh.server.views.ws import WSHandler
  from tests.support.plugins.managed_server_loop import MSL
  from tests.support.util.env import envset
  import bokeh.server.tornado
label_desc: Use image node_id 7 for calling a global function with example usage: test_auth_provider() without return types