Speccing a respond_to block outside of a request

Hi – I have a bunch of controllers whose index actions are so similar,
I can safely stick most of the code in a superclass.
I am having trouble, however, in speccing the index method in the
superclass.
It could look like this: http://pastie.org/240207

This is the class that the controllers that would actually get called
would inherit from.

I want to describe SuperController#index in a spec, so will need to be
able to manipulate the respond_to method – any ideas on how i can do
this?
Also, it would be nice to spec that the before filter has been applied,
if there was a way, but the main thing is the index method.

Cheers for any & all assistance,
Doug.