class_docstr: Tests for horovod.runner.common.service.
code: def test_stream(self):
      sleep = 2.0
      key = secret.make_secret_key()
      service = TestStreamService(key, duration=sleep)
      try:
          client = TestStreamClient(
              service.addresses(), key, attempts=1
          )
  
          start = time.time()
          stream = io.StringIO()
          client.sleep(stream)
          duration = time.time() - start
  
          self.assertEqual(f"slept {sleep}", stream.getvalue())
          self.assertGreaterEqual(duration, 2)
      finally:
          service.shutdown()
  
imports: import io
  import queue
  import threading
  import time
  import unittest
  import warnings
  import pytest
  from horovod.runner.common.service.task_service import BasicTaskClient, BasicTaskService
  from horovod.runner.common.util import network, secret
  from horovod.runner.util.threads import in_thread
  from horovod.runner.util.streams import Pipe
label_desc: Use image node_id 6 for calling the NetworkTests obj's underlying member method code with example usage: obj.test_stream() without return types