Add AttributeAssigner to handle attribute assignment on the build class instance

lib/factory_girl.rb

@@ -4,6 +4,7 @@ require 'factory_girl/proxy'
 require 'factory_girl/registry'
 require 'factory_girl/null_factory'
 require 'factory_girl/factory'
+require 'factory_girl/attribute_assigner'
 require 'factory_girl/evaluator'
 require 'factory_girl/evaluator_class_definer'
 require 'factory_girl/attribute'

lib/factory_girl/attribute_assigner.rb

@@ -0,0 +1,38 @@
+module FactoryGirl
+  class AttributeAssigner
+    attr_reader :evaluator_class_instance
+
+    def initialize(build_class, evaluator_class_instance, attribute_names_to_assign = [])
+      @build_class               = build_class
+      @evaluator_class_instance  = evaluator_class_instance
+      @attribute_names_to_assign = attribute_names_to_assign
+      @attribute_names_assigned  = []
+    end
+
+    def object
+      build_class_instance.tap do |instance|
+        (@attribute_names_to_assign - @attribute_names_assigned).each do |attribute|
+          instance.send("#{attribute}=", get(attribute))
+          @attribute_names_assigned << attribute
+        end
+      end
+    end
+
+    def hash
+      @attribute_names_to_assign.inject({}) do |result, attribute|
+        result[attribute] = get(attribute)
+        result
+      end
+    end
+
+    private
+
+    def build_class_instance
+      @build_class_instance ||= @build_class.new
+    end
+
+    def get(attribute_name)
+      @evaluator_class_instance.send(attribute_name)
+    end
+  end
+end

lib/factory_girl/proxy.rb

@@ -96,16 +96,11 @@ module FactoryGirl
       delegate :set, :attributes, :to => :@evaluator_class_definer
 
       def to_hash
-        attributes.inject({}) do |result, attribute|
-          result[attribute] = get(attribute)
-          result
-        end
+        attribute_assigner.hash
       end
 
       def object
-        @object ||= @klass.new
-        assign_object_attributes
-        @object
+        attribute_assigner.object
       end
 
       def anonymous_instance
@@ -114,16 +109,13 @@ module FactoryGirl
 
       private
 
-      def assign_object_attributes
-        (attributes - @assigned_attributes).each do |attribute|
-          @assigned_attributes << attribute
-          @object.send("#{attribute}=", get(attribute))
-        end
-      end
-
       def get(attribute)
         anonymous_instance.send(attribute)
       end
+
+      def attribute_assigner
+        @attribute_assigner ||= AttributeAssigner.new(@klass, anonymous_instance, attributes)
+      end
     end
   end
 end