code: def test_pl_app_download_frontend(tmp_path):
      build_dir = tmp_path / "app" / "ui" / "build"
      download_frontend(build_dir)
      contents = os.listdir(build_dir)
      assert "index.html" in contents
      assert "static" in contents
  
file_path: pytorch-lightning/tests/tests_app/cli/test_cmd_pl_init.py
imports: import os
  import sys
  from unittest import mock
  from unittest.mock import Mock
  import pytest
  from click.testing import CliRunner
  from lightning.app.cli import lightning_cli
  from lightning.app.cli.cmd_pl_init import _can_encode_icon, download_frontend, pl_app
label_desc: Use image node_id 5 for calling a global function with example usage: test_pl_app_download_frontend(tmp_path) without return types