Testing page caching

posts_controller.rb

class PostsController < ApplicationController
  caches_page :index

  def index
    render text: "html!"
  end
end

posts_controller_spec.rb

require 'spec_helper'

describe PostsController do

  describe "GET index", caching: true do

    around do |example|
      ActionController::Base.perform_caching = true
      Rails.application.config.action_controller.perform_caching = true
      example.run
      ActionController::Base.perform_caching = false
      Rails.application.config.action_controller.perform_caching = false
    end

    it "caches the index page" do
      controller.class.perform_caching.should be_true # true.

      controller.should_receive(:cache_page).and_return true
                # ^ .with("html!", controller: "posts", action: "index")

      get :index
    end
  end

end

Page Caching is implemented as an after_filter:

https://github.com/rails/rails/blob/3-2-stable/actionpack/lib/action_controller/caching/pages.rb#L122

I tested other after_filters, e.g.

after_filter :hit_me

def hit_me
  binding.pry
end

This gets called, but cache_page doesn't...

Turns out page caching only works when perform_caching is set in environments/test.rb.

Turning it on selectively the spec doesn't work: I suspect this is a reloading issue, even though checking perform_caching in the spec example returns true.