Merge pull request #338 from sul-dlss/use_better_http_status_331

Return 500 error instead of 400 when request is OK but underlying data is bad

app/controllers/objects_controller.rb

@@ -12,7 +12,7 @@ class ObjectsController < ApplicationController
   end
 
   rescue_from(DublinCoreService::CrosswalkError) do |e|
-    render status: 400, plain: e.message
+    render status: 500, plain: e.message
   end
 
   # Register new objects in DOR

spec/controllers/objects_controller_spec.rb

@@ -62,10 +62,10 @@
     context 'with bad metadata' do
       let(:error_message) { "DublinCoreService#ng_xml produced incorrect xml (no children):\n<xml/>" }
 
-      it 'returns a 400 error' do
+      it 'returns a 500 error' do
         allow(PublishMetadataService).to receive(:publish).and_raise(DublinCoreService::CrosswalkError, error_message)
         post :publish, params: { id: item.pid }
-        expect(response.status).to eq(400)
+        expect(response.status).to eq(500)
         expect(response.body).to eq(error_message)
       end
     end