code: def test_request_job(self):
      worker_manager = WorkerManager("localhost")
      job_address1 = worker_manager.request_job(n_cpu=1)
      self.assertTrue(job_address1 is None)
  
      worker_manager.add_worker(self.worker1)
      job_address2 = worker_manager.request_job(n_cpu=1)
      self.assertTrue(job_address2 in self.worker1.initialized_jobs)
      self.assertEqual(worker_manager.job_num, 4)
      self.assertEqual(worker_manager.cpu_num, 4)
  
file_path: PARL/parl/remote/tests/worker_manager_test.py
imports: import unittest
  import socket
  from parl.remote.worker_manager import WorkerManager
  from parl.remote.message import InitializedWorker, InitializedJob, AllocatedCpu, AllocatedGpu
label_desc: Use image node_id 4 for calling the ImportTest obj's underlying member method code with example usage: obj.test_request_job() without return types