如何测试 Pundit Headless Policy？答案

【问题标题】：How to test a Pundit Headless Policy?如何测试 Pundit Headless Policy？
【发布时间】：2016-03-22 03:29:17
【问题描述】：

导轨：4.2 权威人士：1.0.1

测试无头策略的策略是什么？当我使用 README 示例中给出的 DSL 时，我遇到了范围界定问题。

管理政策：

class AdminPolicy < ApplicationPolicy

  def initialize user, resource
    @user = user
    @resource = resource
  end

  def manage_any?
    user.present? && user.system_admin_role?
  end
end

rspec：

require 'rails_helper'

describe AdminPolicy do

  subject { described_class }

  context "limited_user" do
    let(:user)     { create :user }
    let(:resource) { nil }

    permissions :show? do
      it { is_expected.to_not permit :manage_any?, resource }
    end
  end

end

错误输出：

  1) AdminPolicy limited_user show? should not permit #<User id: 2380, email: "first1.last1@test.gov", [...], system_admin_role: false> and :manage_any?
     Failure/Error: scope.where(id: resource.id).exists?

     NameError:
       undefined local variable or method `scope' for #<AdminPolicy:0x007fae12e2f618>
     # ./app/policies/application_policy.rb:25:in `show?'
     # /Users/mwlang/.rvm/gems/ruby-2.1.5/gems/pundit-1.0.1/lib/pundit/rspec.rb:15:in `public_send'
     # /Users/mwlang/.rvm/gems/ruby-2.1.5/gems/pundit-1.0.1/lib/pundit/rspec.rb:15:in `block (3 levels) in <module:Matchers>'
     # /Users/mwlang/.rvm/gems/ruby-2.1.5/gems/pundit-1.0.1/lib/pundit/rspec.rb:15:in `each'
     # /Users/mwlang/.rvm/gems/ruby-2.1.5/gems/pundit-1.0.1/lib/pundit/rspec.rb:15:in `find_all'
     # /Users/mwlang/.rvm/gems/ruby-2.1.5/gems/pundit-1.0.1/lib/pundit/rspec.rb:15:in `block (2 levels) in <module:Matchers>'
     # ./spec/policies/admin_policy_spec.rb:13:in `block (4 levels) in <top (required)>'

Finished in 0.41901 seconds (files took 2.02 seconds to load)

【问题讨论】：

标签： ruby-on-rails ruby-on-rails-4 pundit

【解决方案1】：

发布问题后，首先意识到#scope 是如何被调用的。

permissions 块是用:show? 定义的，应该用:manage_any? 定义，这是我真正想测试的上下文。结果，我实际上是从调用范围的 ApplicationPolicy 调用 :show?。

resource 在这种无头上下文中同样不需要，因此请消除它。我们剩下以下内容：

require 'rails_helper'

describe AdminPolicy do

  subject { described_class }

  context "limited_user" do
    let(:user)          { create :user }
    let(:system_admin)  { create :user, system_admin_role: true }

    permissions :manage_any? do
      it { is_expected.to_not permit user }
      it { is_expected.to     permit system_admin }
    end
  end
end

【讨论】：