When I inserted "django-storages" in my INSTALLED_APPS, I was surprised that tons of tests were failing. It turns out a django-storage's test removed all my static content!
Luckily everything was easily recoverable because I use version control software; some other poor soul might no be so lucky.
The problem was my MEDIA_ROOT is set to the same directory as all my static content. This probably shouldn't be the case the test blindly removed MEDIA_ROOT and all that lives under it.
My patch uses a subdirectory of MEDIA_ROOT called 'django-storages-test' and removes that instead of MEDIA_ROOT itself.
My commit message should have read "safer" instead of safe as someone could conceivably have a directory 'MEDIA_ROOT/django-storages-test' they don't want to delete.