Trap for Errno::ENOENT

Fixes #1184

This branch includes the following pieces:
* Trap for `Errno::ENOENT` on first call to `moab_validation_errors`
* When the trap triggers, add a `MOAB_NOT_FOUND` result and update the status to `online_moab_not_found`

Also include:
* Prefer appending arrays of values to iterating and shoveling in `MoabValidationHandler`

app/services/moab_validation_handler.rb

@@ -36,7 +36,7 @@ def moab_validation_errors
         if moab_errors.any?
           moab_error_msgs = []
           moab_errors.each do |error_hash|
-            error_hash.each_value { |msg| moab_error_msgs << msg }
+            moab_error_msgs += error_hash.values
           end
           results.add_result(AuditResults::INVALID_MOAB, moab_error_msgs)
         end
@@ -68,7 +68,15 @@ def update_status(new_status)
   # @param [Boolean] found_expected_version
   # @return [void]
   def set_status_as_seen_on_disk(found_expected_version)
-    return update_status('invalid_moab') if moab_validation_errors.any?
+    begin
+      return update_status('invalid_moab') if moab_validation_errors.any?
+    rescue Errno::ENOENT
+      results.add_result(AuditResults::MOAB_NOT_FOUND,
+                         db_created_at: complete_moab.created_at.iso8601,
+                         db_updated_at: complete_moab.updated_at.iso8601)
+      return update_status('online_moab_not_found')
+    end
+
     return update_status('unexpected_version_on_storage') unless found_expected_version
 
     # NOTE: subclasses which override this method should NOT perform checksum validation inside of this method!

spec/lib/audit/catalog_to_moab_spec.rb

@@ -329,6 +329,27 @@
         expect(new_status).to eq 'unexpected_version_on_storage'
       end
 
+      context 'moab not found' do
+        before do
+          allow(mock_sov).to receive(:validation_errors).and_raise(Errno::ENOENT)
+          allow(Stanford::StorageObjectValidator).to receive(:new).and_return(mock_sov)
+        end
+
+        it 'sets status to online_moab_not_found' do
+          orig = comp_moab.status
+          c2m.check_catalog_version
+          new_status = comp_moab.reload.status
+          expect(new_status).not_to eq orig
+          expect(new_status).to eq 'online_moab_not_found'
+        end
+
+        it 'adds a MOAB_NOT_FOUND result' do
+          c2m.instance_variable_set(:@results, results_double)
+          expect(c2m.results).to receive(:add_result).with(AuditResults::MOAB_NOT_FOUND, anything)
+          c2m.check_catalog_version
+        end
+      end
+
       context 'invalid moab' do
         before do
           allow(mock_sov).to receive(:validation_errors).and_return([foo: 'error message'])