require 'rails_helper' RSpec.describe 'Index overriding', type: :controller do before do load_resources { ActiveAdmin.register Post } @controller = Admin::PostsController.new @controller.instance_eval do def index super do render body: 'Rendered from passed block' return end end end end it 'should call block passed to overridden index' do get :index expect(response.body).to eq 'Rendered from passed block' end end