before/after filters/actions rspec testing. Credits to: http://stackoverflow.com/a/20776916/2047418

application_controller_spec.rb

# spec/controllers/application_controller_spec.rb
require 'spec_helper'
describe ApplicationController do
  describe 'class' do
    it { has_before_filters(:authenticate_user) }
  end
end

controller_macros.rb

# spec/support/controller_macros.rb
module ControllerMacros
  def has_before_filters *names
    expect(controller).to have_filters(:before, *names)
  end
end

have_filters.rb

# spec/support/matchers/have_filters.rb
RSpec::Matchers.define :have_filters do |kind, *names|
  match do |controller|
    filters = controller._process_action_callbacks.select{ |f| f.kind == kind }.map(&:filter)
    names.all?{ |name| filters.include?(name) }
  end
end

spec_helper.rb

# spec/spec_helper.rb
RSpec.configure do |config|
  config.include ControllerMacros, type: :controller
end
and than you can just use it in controller specs like this: