import concurrent.futures
import heapq
import itertools
-import logging
import os
import socket
import subprocess
import unittest
import unittest.mock
import queue as pyqueue
-import contextlib
import time
import io
import itertools
"""Unit tests for contextlib.py, and other context managers."""
-import asyncio
import io
import sys
import tempfile
import sysconfig
import tempfile
import textwrap
-import threading
import unittest
from test import libregrtest
from test import support
import builtins
import contextlib
import copy
-from functools import partial
import io
import os
import pickle