code: def test_process_worker_stop(self):
      self._manager.process_worker("sleep", ["sleep", "3600"])
      self._manager.stop_and_wait()
  
imports: import os
  import signal
  import threading
  import time
  from absl.testing import absltest
  from launchpad.launch import worker_manager
  import mock
label_desc: Use image node_id 12 for calling the WorkerManagerTest obj's underlying member method code with example usage: obj.test_process_worker_stop() without return types