async def METHOD_NAME() -> None:
    loop = asyncio.get_event_loop()
    pr = BaseProtocol(loop=loop)
    tr = mock.Mock()
    pr.connection_made(tr)
    pr.pause_writing()
    t = loop.create_task(pr._drain_helper())
    await asyncio.sleep(0)
    assert pr._drain_waiter is not None
    pr.connection_lost(None)
    await t
    assert pr._drain_waiter is None