code: def test_deployment_without_route(serve_instance):
      @serve.deployment(route_prefix=None)
      class D:
          def __call__(self, *args):
              return "1"
  
      serve.run(D.bind(), route_prefix=None)
      routes = requests.get("http://localhost:8000/-/routes").json()
      assert len(routes) == 0
  
      # make sure the deployment is not exposed under the default route
      r = requests.get("http://localhost:8000/")
      assert r.status_code == 404
  
file_path: ray/python/ray/serve/tests/test_http_routes.py
imports: import time
  import pytest
  import requests
  from fastapi import FastAPI, Request
  from starlette.responses import RedirectResponse
  import ray
  from ray import serve
  from ray.serve._private.constants import SERVE_DEFAULT_APP_NAME
label_desc: Use image node_id 4 for calling a global function with example usage: test_deployment_without_route(serve_instance) and returns: str