code: def test_node_rank(tmp_path):
      environ = {
          "LSB_DJOB_RANKFILE": _make_rankfile(tmp_path),
          "LSB_JOBID": "1234",
          "JSM_NAMESPACE_SIZE": "4",
          "JSM_NAMESPACE_RANK": "3",
          "JSM_NAMESPACE_LOCAL_RANK": "1",
      }
      with mock.patch.dict(os.environ, environ), mock.patch(
          "socket.gethostname", return_value="10.10.10.2"
      ):
          env = LSFEnvironment()
          assert env.node_rank() == 2
  
file_path: pytorch-lightning/tests/tests_fabric/plugins/environments/test_lsf.py
imports: import os
  from unittest import mock
  import pytest
  from lightning.fabric.plugins.environments import LSFEnvironment
label_desc: Use image node_id 7 for calling a global function with example usage: test_node_rank(tmp_path) without return types