code: def test_open_resource(self, mode):
      app = flask.Flask(__name__)
  
      with app.open_resource("static/index.html", mode) as f:
          assert "<h1>Hello World!</h1>" in str(f.read())
  
imports: import io
  import os
  import pytest
  import werkzeug.exceptions
  import flask
  from flask.helpers import get_debug_flag
label_desc: Use image node_id 3 for calling the TestHelpers obj's underlying member method code with example usage: obj.test_open_resource(mode) without return types