Fix payments coming up as $0, credit card charges failing for the same reason

app/controllers/checkout_controller.rb

@@ -15,7 +15,7 @@ class CheckoutController < Spree::CheckoutController
   end
 
   def update
-    if @order.update_attributes(params[:order])
+    if @order.update_attributes(object_params)
       fire_event('spree.checkout.update')
       while @order.state != "complete"
         if @order.state == "payment"
@@ -52,8 +52,23 @@ class CheckoutController < Spree::CheckoutController
     end
   end
 
+
   private
   
+  # Copied and modified from spree. Remove check for order state, since the state machine is
+  # progressed all the way in one go with the one page checkout.
+  def object_params
+    # For payment step, filter order parameters to produce the expected nested attributes for a single payment and its source, discarding attributes for payment methods other than the one selected
+    if params[:payment_source].present? && source_params = params.delete(:payment_source)[params[:order][:payments_attributes].first[:payment_method_id].underscore]
+      params[:order][:payments_attributes].first[:source_attributes] = source_params
+    end
+    if (params[:order][:payments_attributes])
+      params[:order][:payments_attributes].first[:amount] = @order.total
+    end
+    params[:order]
+  end
+
+
   def update_failed
     clear_ship_address
     respond_to do |format|

spec/features/consumer/shopping/checkout_spec.rb

@@ -145,6 +145,10 @@ feature "As a consumer I want to check out my cart", js: true do
 
               place_order
               page.should have_content "Your order has been processed successfully"
+
+              # Order should have a payment with the correct amount
+              o = Spree::Order.complete.first
+              o.payments.first.amount.should == 10
             end
 
             it "shows the payment processing failed message when submitted with an invalid credit card" do

spec/support/request/shop_workflow.rb

@@ -13,6 +13,7 @@ module ShopWorkflow
 
   def add_product_to_cart
     create(:line_item, variant: product.master, order: order)
+    order.reload.save! # Recalculate totals
   end
 
   def toggle_accordion(name)