https://github.com/plataformatec/devise/wiki/How-To:-Stub-authentication-in-controller-specs
These are instructions for allowing you to use resource test doubles instead of actual ActiveRecord objects for testing controllers where Devise interactions are important. This means there's even less reliance on the database for controller specs, and that means faster tests!
This approach certainly needs some evolution, but it's a start.
To stub out your user for an action that expects an authenticated user, you'll want some code like this (once you've got Devise::TestHelpers
loaded):
user = double('user')