Refactor implementation of #reshare_count.

The old implementation which uses Post.where causes

  undefined method `abstract_class?' for Object:Class

in spec/controllers/posts_controller_spec.rb.  Not sure whether that's a problem
with Rails, or rspec, or what.

app/models/post.rb

@@ -54,7 +54,7 @@ class Post < ActiveRecord::Base
   end
 
   def reshare_count
-    @reshare_count ||= Post.where(:root_guid => self.guid).count
+    @reshare_count ||= Post.find_all_by_root_guid(self.guid).count
   end
 
   # @return Returns true if this Post will accept updates (i.e. updates to the caption of a photo).

spec/models/post_spec.rb

@@ -378,4 +378,45 @@ describe Post do
       end
     end
   end
+
+  describe '#reshare_count' do
+    before :each do
+      @post = @user.post :status_message, :text => "hello", :to => @aspect.id, :public => true
+      @post.reshares.size.should == 0
+    end
+
+    describe 'when post has not been reshared' do
+      it 'returns zero' do
+        @post.reshare_count.should == 0
+      end
+    end
+
+    describe 'when post has been reshared exactly 1 time' do
+      before :each do
+        @post.reshares.size.should == 0
+        @reshare = Factory.create(:reshare, :root => @post)
+        @post.reload
+        @post.reshares.size.should == 1
+      end
+
+      it 'returns 1' do
+        @post.reshare_count.should == 1
+      end
+    end
+
+    describe 'when post has been reshared more than once' do
+      before :each do
+        @post.reshares.size.should == 0
+        Factory.create(:reshare, :root => @post)
+        Factory.create(:reshare, :root => @post)
+        Factory.create(:reshare, :root => @post)
+        @post.reload
+        @post.reshares.size.should == 3
+      end
+
+      it 'returns the number of reshares' do
+        @post.reshare_count.should == 3
+      end
+    end
+  end
 end