code: def test_env_variables(
      attr_name: str, value: str, expected_value: Any
  ) -> None:
      env_name = f"GPFLOW_{attr_name.upper()}"
      with mock.patch.dict("os.environ", {env_name: value}):
          assert os.environ[env_name] == value
          config = gpflow.config.Config()
          assert getattr(config, attr_name) == expected_value
  
imports: import os
  from typing import Any, Callable, Iterable
  from unittest import mock
  import numpy
  import pytest
  import tensorflow
  import gpflow
  from gpflow.base import TensorData
  from gpflow.config import config, default_float, default_int, default_jitter, default_likelihood_positive_minimum, default_positive_bijector, default_positive_minimum, default_summary_fmt, set_config, set_default_float, set_default_int, set_default_jitter, set_default_likelihood_positive_minimum, set_default_positive_bijector, set_default_positive_minimum, set_default_summary_fmt
  from gpflow.utilities import to_default_float, to_default_int
label_desc: Use image node_id 2 for calling a global function with example usage: test_env_variables(attr_name, value, expected_value) without return types