Controller_name in rspec-rails2?

I’m trying to use some temporary spec only namespaced controllers with
rspec-rails2 and rails3 and my specs fail saying no method for
‘controller_name’. The same specs work perfectly fine with rails2 and
rspec-rails. Putting the specific controller into the describe doesn’t
work. What is the current way to do this with rspec v2?

Thanks,
Steve