Script to reproduce the `AsyncLibraryNotFoundError` error.

test_run_sync.py

import os

try:
    from anyio.to_thread import run_sync
except ImportError:
    # fallback on anyio v2 for python version < 3.7
    from anyio import run_sync_in_worker_thread as run_sync
import asyncio


async def test():
  await run_sync(os.mkdir, 'test1')


async def main():
    await test()


def clean_up():
  try:
    os.rmdir('test1')
  except FileNotFoundError:
    pass


if __name__ == '__main__':
  clean_up()
  loop = asyncio.get_event_loop()
  loop.run_until_complete(main())
  loop.close()