Tests fail on Celery for Python 3.7 only

[matthewfeickert]

=================================== FAILURES ===================================
__________________________________ test_known __________________________________

    def test_known():
        for known_backend in [
            "celery",
            "multiproc:4",
            "multiproc:auto",
            "foregroundasync",
            "externalasync:default",
        ]:
>           b = backend_from_string(known_backend)

tests/test_backends.py:13: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
packtivity/backendutils.py:192: in backend_from_string
    return backends[k]["default"](backendstring, backendopts)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

backendstring = 'celery', backendopts = {}

    @backend("celery")
    def celery_backend(backendstring, backendopts):
>       backend = asyncbackends.CeleryBackend(**backendopts)
E       AttributeError: module 'packtivity.asyncbackends' has no attribute 'CeleryBackend'

packtivity/backendutils.py:132: AttributeError
_________________________________ test_celery __________________________________

    def test_celery():
>       from packtivity.asyncbackends import CeleryProxy
E       ImportError: cannot import name 'CeleryProxy' from 'packtivity.asyncbackends' (/home/runner/work/packtivity/packtivity/packtivity/asyncbackends.py)

tests/test_proxies.py:5: ImportError

[matthewfeickert]

Seems to be Python 3.7 specific:

$ docker run --rm -ti python:3.7 /bin/bash
root@06c6d53d8eaf:/# python -m venv venv && . venv/bin/activate
(venv) root@06c6d53d8eaf:/# python -m pip --quiet install --upgrade pip setuptools wheel
(venv) root@06c6d53d8eaf:/# python -m pip --quiet install --upgrade celery
(venv) root@06c6d53d8eaf:/# python -m pip show celery
Name: celery
Version: 5.2.7
Summary: Distributed Task Queue.
Home-page: http://celeryproject.org
Author: Ask Solem
Author-email: auvipy@gmail.com
License: BSD
Location: /venv/lib/python3.7/site-packages
Requires: billiard, click, click-didyoumean, click-plugins, click-repl, importlib-metadata, kombu, pytz, vine
Required-by: 
(venv) root@06c6d53d8eaf:/# python -c 'import celery'
(venv) root@06c6d53d8eaf:/# python -c 'from celery import Celery'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ImportError: cannot import name 'Celery' from 'celery' (/venv/lib/python3.7/site-packages/celery/__init__.py)
(venv) root@06c6d53d8eaf:/# 

vs. Python 3.8:

$ docker run --rm -ti python:3.8 /bin/bash
root@aebe940fcecb:/# python -m venv venv && . venv/bin/activate
(venv) root@aebe940fcecb:/# python -m pip --quiet install --upgrade pip setuptools wheel
(venv) root@aebe940fcecb:/# python -m pip --quiet install --upgrade celery
(venv) root@aebe940fcecb:/# python -m pip show celery
Name: celery
Version: 5.2.7
Summary: Distributed Task Queue.
Home-page: http://celeryproject.org
Author: Ask Solem
Author-email: auvipy@gmail.com
License: BSD
Location: /venv/lib/python3.8/site-packages
Requires: billiard, click, click-didyoumean, click-plugins, click-repl, kombu, pytz, vine
Required-by: 
(venv) root@aebe940fcecb:/# python -c 'import celery'
(venv) root@aebe940fcecb:/# python -c 'from celery import Celery'
(venv) root@aebe940fcecb:/# 

[matthewfeickert]

Hm. Seems to be an importlib-metadata issue that won't get fixed until the next release of kombu given celery/celery#7783 (comment).