code: def setUp(self):
      self.test_dir = tempfile.mkdtemp()
      # set a sentinel env var on the parent proc
      # this should be present on the child and gets
      # asserted in ``bin/test_script.py``
      os.environ["TEST_SENTINEL_PARENT"] = "FOOBAR"
  
file_path: pytorch/test/distributed/launcher/launch_test.py
imports: import os
  import shutil
  import tempfile
  import unittest
  from contextlib import closing
  import torch.distributed.launch
  from torch.distributed.elastic.utils import get_socket_with_port
  from torch.testing._internal.common_utils import TEST_WITH_DEV_DBG_ASAN, skip_but_pass_in_sandcastle_if
label_desc: Use image node_id 1 for calling the LaunchTest obj's underlying member method code with example usage: obj.setUp() without return types