Spec before_actions in RSpec

application_controller.rb

class ApplicationController < ActionController::Base
  protect_from_forgery with: :exception

  def current_user
    User.find_by(id: session[:user_id])
  end

  helper_method :current_user

  def ensure_logged_in_user
    unless current_user
      redirect_to signin_path
    end
  end

  before_action :ensure_logged_in_user

end

application_controller_spec.rb

require 'rails_helper'

describe ApplicationController do

  describe "permissions" do
    controller do
      def index
        render nothing: true
      end
    end

    it "redirects non-logged in users to signin" do
      get :index
      expect(response).to redirect_to(signin_path)
    end

    it "allows logged-in users to see pages" do
      session[:user_id] = create_user.id
      get :index
      expect(response).to be_success
    end
  end

end