code: def test_working(self) -> None:
      runtime_name = RUNTIME_NAMES[0]
      exp_working_dir = "/etc"
      rt = Runtime(runtime_name, working_dir=exp_working_dir)
      act_working_dir = rt.echo("${PWD}").rstrip("\n")
      assert exp_working_dir == act_working_dir
  
      task = RuntimeTask("get-working-dir").run_command("echo ${PWD}")
      rt.execute_task(task, execute_async=False)
      assert exp_working_dir == rt.execution_log(task.name)[0].rstrip(
          "\n"
      ).rstrip("\r")
  
imports: import os
  import re
  import sys
  import time
  from subprocess import PIPE, run
  from types import ModuleType
  from typing import Union
  import docker
  import requests
  import storm.__main__
  from lazycluster import Runtime, RuntimeGroup, RuntimeManager, RuntimeTask
  from .config import RUNTIME_DOCKER_IMAGE, RUNTIME_NAMES, WORKSPACE_PORT
label_desc: Use image node_id 3 for calling the TestRuntime obj's underlying member method code with example usage: obj.test_working() without return types