title: How to test rails ETag caching?
body: <p>Is it possible to cover my controller, that is highly depeinding on Etags with unit tests?</p>
  
  <p>Here's what i'm trying to do:
  in case if page is not stale (meaning that it's fresh), i'm adding some header to response.</p>
  
  <p>When i'm trying to test it all (rspec), no matter how many similar requests i have, i still receive 200 OK instead of 304, and my header doesn't get modified. Furthermore, if i track request.fresh?(response), it's ALWAYS false.</p>
  
  <p>However, it perfectly works in browser.
  I've already tried to state ActionController::Base.perform_caching = true, it doesn't change the overall situation.</p>
  
  <p>Thank you</p>