class_docstr: Test the config system.
class_docstr_tok: ["Test","the","config","system","."]
code: def test_maybe_read_env_variable(self):
      self.assertEqual(
          "env:RANDOM_TEST",
          config._maybe_read_env_variable("env:RANDOM_TEST"),
      )
      os.environ["RANDOM_TEST"] = "1234"
      self.assertEqual(
          1234, config._maybe_read_env_variable("env:RANDOM_TEST")
      )
  
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 24 for calling the ConfigTest obj's underlying member method code with example usage: obj.test_maybe_read_env_variable() without return types