code: def test_templatename_app():
      start_dir = os.getcwd()
      os.chdir("..")
  
      cwd = os.getcwd()
      cwd = os.path.join(cwd, "placeholdername/app.py")
      command_line = [
          cwd,
          "--blocking",
          "False",
          "--open-ui",
          "False",
      ]
      result = application_testing(LightningAppTestInt, command_line)
      assert result.exit_code == 0
  
      # reset dir
      os.chdir(start_dir)
  
file_path: pytorch-lightning/src/lightning/app/cli/app-template/tests/test_placeholdername_app.py
imports: import io
  import os
  from contextlib import redirect_stdout
  from lightning.app.testing.testing import LightningTestApp, application_testing
label_desc: Use image node_id 1 for calling a global function with example usage: test_templatename_app() without return types