This PR ports the Celery integration tests to use Maze Runner instead of relying on pytest-celery. The update to pytest-celery v1.0 wasn't particularly straightforward and running Celery with Maze Runner gives us slightly more realistic tests as we aren't relying on any test-only code
This covers exactly the same version ranges as before; Celery 4 on Python 3.5–3.10 and Celery 5 on Python 3.6–3.12
Goal
This PR ports the Celery integration tests to use Maze Runner instead of relying on pytest-celery. The update to pytest-celery v1.0 wasn't particularly straightforward and running Celery with Maze Runner gives us slightly more realistic tests as we aren't relying on any test-only code
This covers exactly the same version ranges as before; Celery 4 on Python 3.5–3.10 and Celery 5 on Python 3.6–3.12