ab_test.rb

require 'action_controller/railtie'

class HelloController < ActionController::Metal
  def index
    self.response_body = "Hello World!"
  end
end

class TestApp < Rails::Application
  config.root = File.dirname(__FILE__)
  config.session_store :cookie_store, key: 'cookie_store_key'
  secrets.secret_token    = 'secret_token'
  secrets.secret_key_base = 'secret_key_base'

  Rails.logger = config.logger = Logger.new($stdout)

  routes.draw do
    get 'index', to: 'hello#index'
  end
end

require 'minitest/autorun'
require 'rack/test'

class BugTest < ActionController::TestCase

  def setup
    @routes = Rails.application.routes
    @controller = HelloController.new
  end

  def test_returns_success
    get :index
    assert_equal "Hello World!", @response.body
  end
end