code: def test_empty_lsb_djob_rankfile():
      """Test an error when the LSB_DJOB_RANKFILE is not populated."""
      with pytest.raises(
          ValueError,
          match="The environment variable `LSB_DJOB_RANKFILE` is empty",
      ):
          LSFEnvironment()
  
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 3 for calling a global function with example usage: test_empty_lsb_djob_rankfile() without return types