Use policy scope to decide which asciicasts should be listed

app/controllers/asciicasts_controller.rb

@@ -9,8 +9,12 @@ class AsciicastsController < ApplicationController
 
   def index
     render locals: {
-      page: BrowsePagePresenter.build(params[:category], params[:order],
-                                      params[:page])
+      page: BrowsePagePresenter.build(
+        policy_scope(Asciicast),
+        params[:category],
+        params[:order],
+        params[:page]
+      )
     }
   end
 

app/models/asciicast.rb

@@ -50,7 +50,7 @@ class Asciicast < ActiveRecord::Base
   end
 
   def self.for_category_ordered(category, order, page = nil, per_page = nil)
-    collection = non_private
+    collection = self
 
     if category == :featured
       collection = collection.featured

app/policies/application_policy.rb

@@ -1,5 +1,14 @@
 class ApplicationPolicy
 
+  class Scope
+    attr_reader :user, :scope
+
+    def initialize(user, scope)
+      @user = user || User.new
+      @scope = scope
+    end
+  end
+
   attr_reader :user, :record
 
   def initialize(user, record)

app/policies/asciicast_policy.rb

@@ -1,8 +1,12 @@
 class AsciicastPolicy < ApplicationPolicy
 
-  class Scope < Struct.new(:user, :scope)
+  class Scope < Scope
     def resolve
-      scope
+      if user.admin?
+        scope.all
+      else
+        scope.non_private
+      end
     end
   end
 

app/presenters/browse_page_presenter.rb

@@ -4,10 +4,11 @@ class BrowsePagePresenter
   DEFAULT_ORDER    = :recency
   PER_PAGE         = 12
 
-  attr_reader :category, :order, :page, :per_page
+  attr_reader :scope, :category, :order, :page, :per_page
 
-  def self.build(category, order, page = nil, per_page = nil)
+  def self.build(scope, category, order, page = nil, per_page = nil)
     new(
+      scope,
       (category || DEFAULT_CATEGORY).to_sym,
       (order    || DEFAULT_ORDER).to_sym,
       page      || 1,
@@ -15,7 +16,8 @@ class BrowsePagePresenter
     )
   end
 
-  def initialize(category, order, page, per_page)
+  def initialize(scope, category, order, page, per_page)
+    @scope    = scope
     @category = category
     @order    = order
     @page     = page
@@ -34,7 +36,7 @@ class BrowsePagePresenter
 
   def get_items
     PaginatingDecorator.new(
-      Asciicast.for_category_ordered(category, order, page, per_page)
+      scope.for_category_ordered(category, order, page, per_page)
     )
   end
 

spec/controllers/asciicasts_controller_spec.rb

@@ -18,22 +18,11 @@ describe AsciicastsController do
   subject { response }
 
   describe '#index' do
-    let(:asciicast_list_presenter) { double('asciicast_list_presenter') }
-
     before do
-      allow(controller).to receive(:render)
-      allow(BrowsePagePresenter).to receive(:build).
-        with('featured', 'recency', '2') { asciicast_list_presenter }
-
       get :index, category: 'featured', order: 'recency', page: '2'
     end
 
     it { should be_success }
-
-    it "renders template with BrowsePagePresenter as page" do
-      expect(controller).to have_received(:render).
-        with(locals: { page: asciicast_list_presenter })
-    end
   end
 
   describe '#show' do

spec/models/asciicast_spec.rb

@@ -62,7 +62,6 @@ describe Asciicast do
     let!(:asciicast_4) { create(:asciicast, created_at:  3.hours.ago,
                                             views_count: 40,
                                             featured:    true) }
-    let!(:asciicast_5) { create(:asciicast, private: true) }
 
     context "when category is :all" do
       let(:category) { :all }

spec/policies/asciicast_policy_spec.rb

@@ -2,6 +2,27 @@ require 'rails_helper'
 
 describe AsciicastPolicy do
 
+  describe AsciicastPolicy::Scope do
+    let(:policy_scope) { AsciicastPolicy::Scope.new(user, Asciicast.all) }
+
+    subject { policy_scope.resolve }
+
+    let!(:asciicast_1) { create(:asciicast, private: false) }
+    let!(:asciicast_2) { create(:asciicast, private: true) }
+
+    context "when user is not admin" do
+      let(:user) { double(:user, admin?: false) }
+
+      it { should eq([asciicast_1]) }
+    end
+
+    context "when user is admin" do
+      let(:user) { double(:user, admin?: true) }
+
+      it { should eq([asciicast_1, asciicast_2]) }
+    end
+  end
+
   subject { described_class }
 
   describe '#permitted_attributes' do

spec/presenters/browse_page_presenter_spec.rb

@@ -3,8 +3,9 @@ require 'rails_helper'
 describe BrowsePagePresenter do
 
   describe '.build' do
-    subject { described_class.build(category, order, page, per_page) }
+    subject { described_class.build(scope, category, order, page, per_page) }
 
+    let(:scope) { double('scope') }
     let(:category) { 'awesome' }
     let(:order) { 'awesomeness' }
     let(:page) { 2 }
@@ -59,7 +60,8 @@ describe BrowsePagePresenter do
     end
   end
 
-  let(:presenter) { described_class.new(category, order, page, per_page) }
+  let(:presenter) { described_class.new(scope, category, order, page, per_page) }
+  let(:scope) { double('scope') }
   let(:category) { :awesome }
   let(:order) { :awesomeness }
   let(:page) { 2 }
@@ -78,13 +80,13 @@ describe BrowsePagePresenter do
     let(:asciicast) { double('asciicast', decorate: double(title: 'quux')) }
 
     before do
-      allow(Asciicast).to receive(:for_category_ordered) { collection }
+      allow(scope).to receive(:for_category_ordered) { collection }
     end
 
     it "gets the asciicasts for given category, order, page and per_page" do
       subject
 
-      expect(Asciicast).to have_received(:for_category_ordered).
+      expect(scope).to have_received(:for_category_ordered).
         with(:awesome, :awesomeness, 2, 5)
     end