Ruby on rails hartl rails教程第9章电子邮件方法错误？

我正在编写Michael Hartl的Ruby on Rails教程，在第9章中遇到了一个错误

错误：

  1) Error:
UsersIndexTest#test_index_as_admin_including_pagination_and_delete_links:
NoMethodError: undefined method `email' for nil:NilClass
    test/test_helper.rb:18:in `log_in_as'
    test/integration/users_index_test.rb:11:in `block in <class:UsersIndexTest>'

36 runs, 79 assertions, 0 failures, 1 errors, 0 skips

我不知道如何修复这个错误。。。非常感谢您的帮助

编辑：

文件：app/controllers/user\u controller.rb

class UsersController < ApplicationController
  before_action :logged_in_user, only: [:index, :edit, :update, :destroy]
  before_action :correct_user,   only: [:edit, :update]
  before_action :admin_user,     only: :destroy

  def index
    @users = User.paginate(page: params[:page])
  end

  def show
    @user = User.find(params[:id])
  end

  def new
    @user = User.new
  end

  def create
    @user = User.new(user_params)
    if @user.save
      log_in @user
      flash[:success] = "Welcome to the Sample App!"
      redirect_to @user
    else
      render 'new'
    end
  end

  def edit
    @user = User.find(params[:id])
  end

  def update
    @user = User.find(params[:id])
    if @user.update_attributes(user_params)
      flash[:success] = "Profile updated"
      redirect_to @user
    else
      render 'edit'
    end
  end

  def destroy
    User.find(params[:id]).destroy
    flash[:success] = "User deleted"
    redirect_to users_url
  end

  private

    def user_params
      params.require(:user).permit(:name, :email, :password,
                                 :password_confirmation)
    end

    # Before filters

    # Confirms a logged-in user.
    def logged_in_user
      unless logged_in?
        store_location
        flash[:danger] = "Please log in."
        redirect_to login_url
      end
    end

    # Confirms the correct user.
    def correct_user
      @user = User.find(params[:id])
      redirect_to(root_url) unless current_user?(@user)
    end

    # Confirms an admin user.
    def admin_user
      redirect_to(root_url) unless current_user.admin?
    end
end

---

在测试设置中，您需要将@user更改为@admin:

---

这是在测试的其余部分中引用的实例变量名。由于未正确设置，@admin为零，导致测试设置中出现错误，因此需要将@user更改为@admin：

---

这是在测试的其余部分中引用的实例变量名。由于设置不正确，@admin为零，导致错误

您在哪里定义@admin？因为您正在呼叫登录_as@admin但是我不知道它是在哪里定义的。你没有定义@admin，我能想到的唯一地方就是user_controller.rb文件或db/schema.rb文件。我已经附加了这两个，但我仍然不确定如何解决这个问题。你在哪里定义@admin？因为您正在呼叫登录_as@admin但是我不知道它是在哪里定义的。你没有定义@admin，我能想到的唯一地方就是user_controller.rb文件或db/schema.rb文件。我已经附上了两个，但我仍然不确定如何解决这个问题。太好了！谢谢dwenzel和所有发表评论的人！回到教程！伟大的谢谢dwenzel和所有发表评论的人！回到教程！

ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../../config/environment', __FILE__)
require 'rails/test_help'

class ActiveSupport::TestCase
  fixtures :all

  # Returns true if a test user is logged in.
  def is_logged_in?
    !session[:user_id].nil?
  end

  # Logs in a test user.
  def log_in_as(user, options = {})
    password    = options[:password]    || 'password'
    remember_me = options[:remember_me] || '1'
    if integration_test?
      post login_path, session: { email:       user.email,
                                  password:    password,
                                  remember_me: remember_me }
    else
      session[:user_id] = user.id
    end
  end

  private

    # Returns true inside an integration test.
    def integration_test?
      defined?(post_via_redirect)
    end
end

class UsersController < ApplicationController
  before_action :logged_in_user, only: [:index, :edit, :update, :destroy]
  before_action :correct_user,   only: [:edit, :update]
  before_action :admin_user,     only: :destroy

  def index
    @users = User.paginate(page: params[:page])
  end

  def show
    @user = User.find(params[:id])
  end

  def new
    @user = User.new
  end

  def create
    @user = User.new(user_params)
    if @user.save
      log_in @user
      flash[:success] = "Welcome to the Sample App!"
      redirect_to @user
    else
      render 'new'
    end
  end

  def edit
    @user = User.find(params[:id])
  end

  def update
    @user = User.find(params[:id])
    if @user.update_attributes(user_params)
      flash[:success] = "Profile updated"
      redirect_to @user
    else
      render 'edit'
    end
  end

  def destroy
    User.find(params[:id]).destroy
    flash[:success] = "User deleted"
    redirect_to users_url
  end

  private

    def user_params
      params.require(:user).permit(:name, :email, :password,
                                 :password_confirmation)
    end

    # Before filters

    # Confirms a logged-in user.
    def logged_in_user
      unless logged_in?
        store_location
        flash[:danger] = "Please log in."
        redirect_to login_url
      end
    end

    # Confirms the correct user.
    def correct_user
      @user = User.find(params[:id])
      redirect_to(root_url) unless current_user?(@user)
    end

    # Confirms an admin user.
    def admin_user
      redirect_to(root_url) unless current_user.admin?
    end
end

ActiveRecord::Schema.define(version: 20150418002759) do

  create_table "users", force: :cascade do |t|
    t.string   "name"
    t.string   "email"
    t.datetime "created_at",                      null: false
    t.datetime "updated_at",                      null: false
    t.string   "password_digest"
    t.string   "remember_digest"
    t.boolean  "admin",           default: false
  end

  add_index "users", ["email"], name: "index_users_on_email", unique: true

end

  def setup
    @admin = users(:michael)
    @non_admin = users(:archer)
  end