code: def test_oserrors_are_reraised():
      """Verify that unexpected OSErrors will cause the Manager to reraise."""
      err = OSError(errno.EAGAIN, "Ominous message")
      with mock.patch("_multiprocessing.SemLock", side_effect=err):
          manager = _parallel_checker_manager()
          with mock.patch.object(manager, "run_serial") as serial:
              with pytest.raises(OSError):
                  manager.run()
      assert serial.call_count == 0
  
file_path: flake8/tests/unit/test_checker_manager.py
imports: from __future__ import annotations
  import errno
  import multiprocessing
  from unittest import mock
  import pytest
  from flake8 import checker
  from flake8.main.options import JobsArgument
  from flake8.plugins import finder
label_desc: Use image node_id 4 for calling a global function with example usage: test_oserrors_are_reraised() without return types