code: def test_no_slash_route_prefix(serve_instance):
      """Test serve run with no slash route_prefix.
  
      This test ensure when serve runs with no prefix slash in route_prefix, it will throw
      good error message.
      """
  
      @serve.deployment
      def f():
          pass
  
      with pytest.raises(
          ValueError,
          match=r"The route_prefix must start with a forward slash \('/'\)",
      ):
          serve.run(f.bind(), route_prefix="no_slash")
  
imports: import asyncio
  import os
  import sys
  from typing import Dict, Optional
  import pytest
  import requests
  import starlette.responses
  from fastapi import FastAPI
  import ray
  from ray import serve
  from ray._private.pydantic_compat import BaseModel, ValidationError
  from ray._private.test_utils import SignalActor, wait_for_condition
  from ray.serve._private.api import call_app_builder_with_args_if_necessary
  from ray.serve._private.common import DeploymentID
  from ray.serve._private.constants import SERVE_DEFAULT_APP_NAME
  from ray.serve.deployment import Application
  from ray.serve.exceptions import RayServeException
  from ray.serve.handle import DeploymentHandle, RayServeHandle
label_desc: Use image node_id 26 for calling a global function with example usage: test_no_slash_route_prefix(serve_instance) without return types