code: def test_log_filenames_contain_only_posix_characters(serve_instance):
      """Assert that all log filenames only consist of POSIX-compliant characters.
  
      See: https://github.com/ray-project/ray/issues/41615
      """
  
      @serve.deployment
      class A:
          def __call__(self, *args) -> str:
              return "hi"
  
      serve.run(A.bind())
  
      r = requests.get("http://localhost:8000/")
      r.raise_for_status()
      assert r.text == "hi"
  
      acceptable_chars = (
          string.ascii_letters + string.digits + "_" + "."
      )
      for filename in os.listdir(get_serve_logs_dir()):
          assert all(char in acceptable_chars for char in filename)
  
imports: import io
  import json
  import logging
  import os
  import re
  import string
  import sys
  import time
  from contextlib import redirect_stderr
  import pytest
  import requests
  import starlette
  import ray
  import ray.util.state
  from ray import serve
  from ray._private.test_utils import wait_for_condition
  from ray.serve._private.common import ServeComponentType
  from ray.serve._private.constants import SERVE_LOG_EXTRA_FIELDS
  from ray.serve._private.logging_utils import ServeJSONFormatter, get_component_log_file_name, get_serve_logs_dir
label_desc: Use image node_id 8 for calling a global function with example usage: test_log_filenames_contain_only_posix_characters(serve_instance) and returns: str