class_docstr: Test the config system.
class_docstr_tok: ["Test","the","config","system","."]
code: def test_server_headless_via_atom_plugin(self):
      os.environ["IS_RUNNING_IN_STREAMLIT_EDITOR_PLUGIN"] = "True"
  
      self.assertEqual(True, config.get_option("server.headless"))
  
      del os.environ["IS_RUNNING_IN_STREAMLIT_EDITOR_PLUGIN"]
  
imports: import copy
  import os
  import textwrap
  import unittest
  from unittest.mock import MagicMock, mock_open, patch
  import pytest
  from parameterized import parameterized
  from streamlit import config, env_util
  from streamlit.config_option import ConfigOption
  from streamlit.errors import StreamlitAPIException
label_desc: Use image node_id 33 for calling the ConfigTest obj's underlying member method code with example usage: obj.test_server_headless_via_atom_plugin() without return types