code: def test_install_app_shows_error(tmpdir):
      app_folder_dir = Path(tmpdir / "some_random_directory").absolute()
      app_folder_dir.mkdir()
  
      with pytest.raises(
          SystemExit,
          match=f"Folder {str(app_folder_dir)} exists, please delete it and try again.",
      ):
          cmd_install._install_app_from_source(
              source_url=mock.ANY,
              git_url=mock.ANY,
              folder_name=str(app_folder_dir),
              overwrite=False,
          )
  
imports: import os
  import subprocess
  from pathlib import Path
  from unittest import mock
  import pytest
  from click.testing import CliRunner
  from lightning.app.cli import cmd_install, lightning_cli
  from lightning.app.testing.helpers import _RunIf
label_desc: Use image node_id 12 for calling a global function with example usage: test_install_app_shows_error(tmpdir) without return types