code: def test_healthz():
      assert _healthz() == {"status": "ok"}
  
file_path: pytorch-lightning/tests/tests_app/frontend/test_web.py
imports: import os
  from unittest import mock
  from unittest.mock import ANY, MagicMock
  import lightning.app
  import pytest
  from lightning.app import LightningFlow
  from lightning.app.frontend.web import StaticWebFrontend, _healthz
  from lightning.app.storage.path import _storage_root_dir
label_desc: Use image node_id 4 for calling a global function with example usage: test_healthz() without return types