Handle all errors when dealing with payment event

This basically catches ActiveRecord::RecordInvalid caused by an invalid
credit record, for instance, but also other situations we haven't
forseen.

app/controllers/spree/admin/payments_controller.rb

@@ -61,7 +61,7 @@ module Spree
         else
           flash[:error] = t(:cannot_perform_operation)
         end
-      rescue Spree::Core::GatewayError => e
+      rescue StandardError => e
         flash[:error] = e.message
       ensure
         redirect_to request.referer

app/models/spree/payment/processing.rb

@@ -108,7 +108,7 @@ module Spree
           record_response(response)
 
           if response.success?
-            self.class.create(
+            self.class.create!(
               order: order,
               source: self,
               payment_method: payment_method,

spec/controllers/spree/admin/orders/payments/payments_controller_spec.rb

@@ -148,8 +148,9 @@ describe Spree::Admin::PaymentsController, type: :controller do
 
       let(:params) { { e: 'credit', order_id: order.number, id: payment.id } }
 
+      before { allow(request).to receive(:referer) { 'http://foo.com' } }
+
       it 'handles gateway errors' do
-        allow(request).to receive(:referer) { 'http://foo.com' }
         allow_any_instance_of(payment_method.class)
           .to receive(:credit).and_raise(Spree::Core::GatewayError, 'error message')
 
@@ -158,6 +159,16 @@ describe Spree::Admin::PaymentsController, type: :controller do
         expect(flash[:error]).to eq('error message')
         expect(response).to redirect_to('http://foo.com')
       end
+
+      it 'handles validation errors' do
+        allow(Spree::Payment).to receive(:find).with(payment.id.to_s) { payment }
+        allow(payment).to receive(:credit!).and_raise(StandardError, 'validation error')
+
+        spree_put :fire, params
+
+        expect(flash[:error]).to eq('validation error')
+        expect(response).to redirect_to('http://foo.com')
+      end
     end
   end
 end

spec/models/spree/payment_spec.rb

@@ -391,7 +391,7 @@ describe Spree::Payment do
 
         context "when response is successful" do
           it "should create an offsetting payment" do
-            Spree::Payment.should_receive(:create)
+            Spree::Payment.should_receive(:create!)
             payment.credit!
           end