async generator closing

test.py

import asyncio
import pytest

@pytest.mark.asyncio
async def test_close_asyncgen():

    loop = asyncio.get_event_loop()

    async def mygen():
        print('mygen: 0-begin')
        await asyncio.sleep(0.4)
        print('mygen: 1')
        yield 1
        print('mygen: 2')
        await asyncio.sleep(0.4)
        print('mygen: 3')
        yield 2
        print('mygen: 4')
        await asyncio.sleep(0.4)
        print('mygen: 5-end')

    g = mygen()

    async def intr():
        nonlocal g
        await asyncio.sleep(0.6)
        print('intr: aclosing')
        await g.aclose()  # expected: raise an error since generator is running
        print('intr: aclosed')

    t = loop.create_task(intr())
    print('test: begin of async-for')
    async for v in g:
        print('test: generated', v)
    print('test: end of async-for')  # not reached???