amend request takes a rate plan with either the product rate plan id …

…or the amendment rate plan id set

lib/zuora/objects/amend_request.rb

@@ -78,7 +78,9 @@ def generate_rate_plan_data(builder)
 
         builder.__send__(ons, :RatePlanData) do |rpd|
           rpd.__send__(zns, :RatePlan) do |rp|
-            rp.__send__(ons, :ProductRatePlanId, rate_plan.id)
+            rate_plan.to_hash.each do |k,v|
+              rp.__send__(ons, k.to_s.zuora_camelize.to_sym, v) unless v.nil?
+            end
           end
           charges.each do |charge|
             rpd.__send__(zns, :RatePlanChargeData) do |rpcd|

spec/zuora/objects/amend_request_spec.rb

@@ -16,13 +16,18 @@
       @amendment = FactoryGirl.build(:amendment)
       @amendment.subscription_id = subscription.id
       MockResponse.responds_with(:payment_method_credit_card_find_success) do
-        @product_rate_plans = [Zuora::Objects::ProductRatePlan.find('stub')]
+        product_rate_plans = [Zuora::Objects::ProductRatePlan.find('stub')]
+
+        @prps = Zuora::Objects::RatePlan.new
+        @prps.product_rate_plan_id = product_rate_plans[0].id
+        @product_rate_plans = [@prps]
       end
     end
 
     it "provides properly formatted xml when using existing objects" do
       MockResponse.responds_with(:amend_request_success) do
         subject.amendment = @amendment
+
         subject.plans_and_charges = Array.new << { rate_plan: @product_rate_plans[0], charges: nil }
         amnd_resp = subject.create
         amnd_resp[:success].should == true