Ruby on rails 授权策略未正确初始化

我正在练习Rails 4中的动作（清单8-12）。我安装了pundit gem并编写了测试，Rspec给了我奇怪的错误：

    1) ProjectPolicy show? blocks anonymous users
 Failure/Error:
   def initialize(user, record)
     @user = user
     @record = record

 ArgumentError:
   wrong number of arguments (given 0, expected 2)
 # ./app/policies/application_policy.rb:4:in `initialize'
 # ./spec/policies/project_policy_spec.rb:10:in `block (3 levels) in <top (required)>'

应用程序策略（如果是由gem自动生成的，则没有任何更改）

---

其余部分省略了

您是否遵循权威文档中的指导原则@Zettetic我根据文档更新了规范，它成功了，谢谢！我不得不添加一行

subject{descripted_class}

，这在书中并没有说明。

describe ProjectPolicy do

permissions :show? do
  let(:user) { FactoryGirl.create :user }
  let(:project) { FactoryGirl.create :project }

  it "blocks anonymous users" do
    expect(subject).not_to permit(nil, project)
  end
end

end

class ApplicationPolicy
attr_reader :user, :record

def initialize(user, record)
  @user = user
  @record = record
end