dont create a object for a has one relationship unnecessarily just to fetch id

lib/fast_jsonapi/serialization_core.rb

@@ -185,11 +185,7 @@ module FastJsonapi
           return object.id
         end
 
-        if relationship[:relationship_type] == :has_one
+        record.public_send(relationship[:id_method_name])
-          record.public_send(relationship[:object_method_name]).try(:id)
-        else
-          record.public_send(relationship[:id_method_name])
-        end
       end
     end
   end

spec/lib/object_serializer_inheritance_spec.rb

@@ -30,6 +30,10 @@ describe FastJsonapi::ObjectSerializer do
       p.user_id = id
       p
     end
+
+    def photo_id
+      1
+    end
   end
 
   class UserSerializer
@@ -77,6 +81,10 @@ describe FastJsonapi::ObjectSerializer do
       a.employee_id = id
       a
     end
+
+    def account_id
+      1
+    end
   end
 
   class EmployeeSerializer < UserSerializer

spec/shared/contexts/movie_context.rb

@@ -31,6 +31,10 @@ RSpec.shared_context 'movie class' do
         mt
       end
 
+      def advertising_campaign_id
+        1
+      end
+
       def advertising_campaign
         ac = AdvertisingCampaign.new
         ac.id = 1
@@ -284,7 +288,7 @@ RSpec.shared_context 'movie class' do
       :owner_id,
       :owner,
       :movie_type_id,
-      :advertising_campaign
+      :advertising_campaign_id
     )
 
     ActorStruct = Struct.new(:id, :name, :email, :agency_id, :award_ids)