code: def setUp(self):
      super().setUp()
      worker_manager._HAS_MAIN_MANAGER = False
      self._sigterm_patcher = mock.patch.object(
          signal, "SIGTERM", new=signal.SIGUSR1
      )
      self._sigterm_patcher.start()
      self._sigint_patcher = mock.patch.object(
          signal, "SIGINT", new=signal.SIGUSR2
      )
      self._sigint_patcher.start()
      self._manager = worker_manager.WorkerManager()
      self.addCleanup(self._manager.cleanup_after_test, self)
  
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 1 for calling the WorkerManagerTest obj's underlying member method code with example usage: obj.setUp() without return types