ruby-on-rails - Michael Hartl チュートリアルの第 8 章のエラー

Question

Michael Hartl のチュートリアルを実行していますが、テストするたびにこのエラーが発生し続けますspec/models/user_spec.rb

rails_projects/sample_app/app/controllers/application_controller.rb:3:in `<class:ApplicationController>': uninitialized constant ApplicationController::SessionsHelper (NameError)

これは私のapplication_controller.rbファイルです

class ApplicationController < ActionController::Base
  protect_from_forgery
  include SessionsHelper

  # Force signout to prevent CSRF attacks
  def handle_unverified_request
    sign_out
    super
  end 

end

これは私のspec/models/user_spec.rbファイルです

# == Schema Information
#
# Table name: users
#
#  id         :integer          not null, primary key
#  name       :string(255)
#  email      :string(255)
#  created_at :datetime         not null
#  updated_at :datetime         not null
#

require 'spec_helper'

describe User do

  @user = User.new(name: "Example User", email: "user@example.com", password: "foobar", password_confirmation: "foobar")
end

subject { @user }

  it { should respond_to(:name) }
  it { should respond_to(:email) }
  it { should respond_to(:password_digest) }
  it { should respond_to(:password) }
  it { should respond_to(:password_confirmation) }
  it { should respond_to(:remember_token) }
  it { should respond_to(:authenticate) }

  it { should be_valid }

describe "when name is not present" do
    before { @user.name = " " }
    it { should_not be_valid }
end

describe "when email is not present" do
    before { @user.email = " " }
    it { should_not be_valid }
end

describe "when name is too long" do
    before { @user.name = "a" * 51 }
    it { should_not be_valid }
end

describe "when email format is invalid" do
    it "should be invalid" do
      addresses = %w[user@foo,com user_at_foo.org example.user@foo.
                     foo@bar_baz.com foo@bar+baz.com]
      addresses.each do |invalid_address|
        @user.email = invalid_address
        @user.should_not be_valid
    end
end
describe "when email format is valid" do
    it "should be valid" do
      addresses = %w[user@foo.COM A_US-ER@f.b.org frst.lst@foo.jp a+b@baz.cn]
      addresses.each do |valid_address|
        @user.email = valid_address
        @user.should be_valid
    end
end

describe "when email address is already taken" do
    before do
      user_with_same_email = @user.dup
      user_with_same_email.email = @user.email.upcase
      user_with_same_email.save
end
    it { should_not be_valid }
  end 
end

describe "when password is not present" do
    before { @user.password = @user.password_confirmation = " " }
    it { should_not be_valid }
  end
end

describe "when password doesn't match confirmation" do
    before { @user.password_confirmation = "mismatch" }
    it { should_not be_valid }
end

describe "when password confirmation is nil" do
    before { @user.password_confirmation = nil }
    it { should_not be_valid }
end

describe "with a password that's too short" do
    before { @user.password = @user.password_confirmation = "a" * 5 }
    it { should be_invalid }
end

describe "return value of authenticate method" do
    before { @user.save }
    let(:found_user) { User.find_by_email(@user.email) }

describe "with valid password" do
      it { should == found_user.authenticate(@user.password) }
end

describe "with invalid password" do
      let(:user_for_invalid_password) { found_user.authenticate("invalid") }
      it { should_not == user_for_invalid_password }
      specify { user_for_invalid_password.should be_false }
  end
end