code: def test_main_address_and_port_from_env_variable():
      env = SLURMEnvironment()
      with mock.patch.dict(
          os.environ, {"MASTER_ADDR": "1.2.3.4", "MASTER_PORT": "1234"}
      ):
          assert env.main_address == "1.2.3.4"
          assert env.main_port == 1234
  
file_path: pytorch-lightning/tests/tests_fabric/plugins/environments/test_slurm.py
imports: import logging
  import os
  import shutil
  import sys
  from unittest import mock
  import pytest
  from lightning.fabric.plugins.environments import SLURMEnvironment
  from lightning.fabric.utilities.warnings import PossibleUserWarning
  from lightning_utilities.test.warning import no_warning_call
  from tests_fabric.helpers.runif import RunIf
label_desc: Use image node_id 4 for calling a global function with example usage: test_main_address_and_port_from_env_variable() without return types