Add with option to decorates_association to allow the decoration to be decorated by a specific association

lib/draper/base.rb

@@ -57,12 +57,17 @@ module Draper
     # the assocation to be decorated when it is retrieved.
     #
     # @param [Symbol] name of association to decorate, like `:products`
-    def self.decorates_association(association_symbol)
+    # @option opts [Class] :with The decorator to decorate the association with
+    def self.decorates_association(association_symbol, options = {})
       define_method(association_symbol) do
         orig_association = model.send(association_symbol)
         return orig_association  if orig_association.nil?
-        reflection = model.class.reflect_on_association(association_symbol)
-        "#{reflection.klass}Decorator".constantize.decorate(orig_association)
+        if options[:with]
+          options[:with].decorate(orig_association)
+        else
+          reflection = model.class.reflect_on_association(association_symbol)
+          "#{reflection.klass}Decorator".constantize.decorate(orig_association)
+        end
       end
     end
 

spec/draper/base_spec.rb

@@ -93,6 +93,13 @@ describe Draper::Base do
         subject.previous_version.should be_nil
       end
     end
+
+    context "with a specific decorator specified" do
+      before(:each){ subject.class_eval{ decorates_association :previous_version, :with => SpecificProductDecorator } }
+      it "causes the association to be decorated with the specified association" do
+        subject.previous_version.should be_instance_of(SpecificProductDecorator)
+      end
+    end
   end
 
   context('.decorates_associations') do

spec/support/samples/specific_product_decorator.rb

@@ -0,0 +1,2 @@
+class SpecificProductDecorator < ProductDecorator
+end