code: def test_job_creation_with_delay(self):
      fiber.backend.get_backend(name="docker")
      old_backend = fiber.backend._backends["docker"]
      fiber.backend._backends["docker"] = DelayedBackend()
  
      p = fiber.Pool(4)
      # explicitly start workers instead of lazy start
      p.start_workers()
      p.wait_until_workers_up()
  
      res = p.map(square_worker, [1, 2, 3, 4])
  
      p.terminate()
      fiber.backend._backends["docker"] = old_backend
  
      assert res == [i**2 for i in range(1, 5)]
  
      # wait for 2 seconds to let docker finish starting
      # time.sleep(2)
      p.join()
  
imports: import fiber
  import multiprocessing
  import time
  import pytest
  import docker
  import fiber.config
  from fiber.docker_backend import Backend
  from fiber.util import find_ip_by_net_interface
  import psutil
  import ipaddress
  import socket
label_desc: Use image node_id 4 for calling the TestDockerBackend obj's underlying member method code with example usage: obj.test_job_creation_with_delay() without return types