[Answer]-Strange warning on my tests

The author of the django-rosetta package needs to update the use of the cycle tag.

What the warning means is that the Django developers have identified a problem with the way cycle is being used by the current version of django-rosetta, and they plan to remove that functionality in a future release. https://docs.djangoproject.com/en/dev/releases/1.9/#cycle-syntax-with-comma-separated-arguments

Generally speaking, you can ignore warnings like this for now. It will become a problem when you upgrade to a version of Django where the deprecated feature is removed or no longer supported.