code: def runner(app):
      return app.test_cli_runner()
  
file_path: cornac/tests/cornac/serving/test_app.py
imports: import os
  import pytest
  from cornac.data import Reader, Dataset
  from cornac.models import BPR
label_desc: Use image node_id 4 for calling a global function with example usage: runner(app) and returns: app