code: def test_add_option_long_option_only(optmanager):
      """Verify the behaviour of adding a long-option only."""
      assert optmanager.options == []
      assert optmanager.config_options_dict == {}
  
      optmanager.add_option("--long", help="Test long opt")
      assert optmanager.options[0].short_option_name is manager._ARG.NO
      assert optmanager.options[0].long_option_name == "--long"
  
imports: from __future__ import annotations
  import argparse
  import os
  import pytest
  from flake8.main.options import JobsArgument
  from flake8.options import manager
label_desc: Use image node_id 7 for calling a global function with example usage: test_add_option_long_option_only(optmanager) without return types