code: def test_run(self):
      async def f():
          await asyncio.sleep(0)
          return "done"
  
      with asyncio.Runner() as runner:
          self.assertEqual("done", runner.run(f()))
          loop = runner.get_loop()
  
      with self.assertRaisesRegex(RuntimeError, "Runner is closed"):
          runner.get_loop()
  
      self.assertTrue(loop.is_closed())
  
imports: import _thread
  import asyncio
  import contextvars
  import re
  import signal
  import sys
  import threading
  import unittest
  from test.test_asyncio import utils
  from unittest import mock
  from unittest.mock import patch
label_desc: Use image node_id 4 for calling the RunnerTests obj's underlying member method code with example usage: obj.test_run() and returns: str