docstr: Ensures that the log tail can gracefully handle no log files
  in which case it does nothing.
docstr_tok: ["Ensures","that","the","log","tail","can","gracefully","handle","no","log","files","in","which","case","it","does","nothing","."]
code: def test_tail_no_files(self):
      """
      Ensures that the log tail can gracefully handle no log files
      in which case it does nothing.
      """
      tail = TailLog("writer", log_files={}, dst=sys.stdout).start()
      self.assertFalse(tail.stopped())
      tail.stop()
      self.assertTrue(tail.stopped())
  
imports: import io
  import os
  import shutil
  import sys
  import tempfile
  import time
  import unittest
  from concurrent.futures import wait
  from concurrent.futures._base import ALL_COMPLETED
  from concurrent.futures.thread import ThreadPoolExecutor
  from typing import Dict, Set
  from unittest import mock
  from torch.distributed.elastic.multiprocessing.tail_log import TailLog
label_desc: Use image node_id 5 for calling the TailLogTest obj's underlying member method code with example usage: obj.test_tail_no_files() without return types