add dedicated intro post set

app/logical/post_sets/intro.rb

@@ -0,0 +1,15 @@
+module PostSets
+  class Intro < PostSets::Post
+    def initialize(tags)
+      super(tags)
+    end
+
+    def posts
+      @posts ||= begin
+        temp = ::Post.tag_match("#{tag_string} fav_count:>3").paginate(page, :search_count => nil, :limit => 6)
+        temp.all
+        temp
+      end
+    end
+  end
+end

app/presenters/intro_presenter.rb

@@ -5,7 +5,7 @@ class IntroPresenter
 
   def each
     popular_tags.each do |tag|
-      yield(tag, PostSets::Post.new(tag, 1, 6))
+      yield(tag, PostSets::Intro.new(tag))
     end
   end
 end

test/unit/post_sets/intro_test.rb

@@ -0,0 +1,42 @@
+require 'test_helper'
+require "danbooru/paginator/pagination_error"
+
+module PostSets
+  class IntroTest < ActiveSupport::TestCase
+    context "In all cases" do
+      setup do
+        @user = FactoryGirl.create(:user)
+        CurrentUser.user = @user
+        CurrentUser.ip_addr = "127.0.0.1"
+        MEMCACHE.flush_all
+
+        @post_1 = FactoryGirl.create(:post, :tag_string => "a")
+        @post_2 = FactoryGirl.create(:post, :tag_string => "b")
+        @post_3 = FactoryGirl.create(:post, :tag_string => "c")
+      end
+
+      teardown do
+        CurrentUser.user = nil
+        CurrentUser.ip_addr = nil
+      end
+
+      context "a set for the 'a' tag query" do
+        setup do
+          @post_4 = FactoryGirl.create(:post, :tag_string => "a")
+          @post_5 = FactoryGirl.create(:post, :tag_string => "a")
+        end
+
+        context "with no page" do
+          setup do
+            @set = PostSets::Intro.new("a")
+            ::Post.stubs(:records_per_page).returns(1)
+          end
+
+          should "return the first element" do
+            assert_equal(@post_5.id, @set.posts.first.id)
+          end
+        end
+      end
+    end
+  end
+end