Fix specs and refactor

Author: johnnyshields

lib/mongoid/fields.rb

@@ -745,19 +745,19 @@ def remove_defaults(name)
         post_processed_defaults.delete_one(name)
       end
 
-      def field_for(name, options)
+      def field_for(field_name, options)
         opts = options.merge(klass: self)
-        if type = options[:type]
-          type = Fields::FieldTypes.get(type)
-          unless type
-            raise Mongoid::Errors::UnknownFieldType.new(self.name, name, type)
-          end
-          opts[:type] = type
-          warn_unsupported_bson_type(type)
-        end
-        return Fields::Localized.new(name, opts) if options[:localize]
-        return Fields::ForeignKey.new(name, opts) if options[:identity]
-        Fields::Standard.new(name, opts)
+        opts[:type] = get_field_type(field_name, options[:type])
+        return Fields::Localized.new(field_name, opts) if options[:localize]
+        return Fields::ForeignKey.new(field_name, opts) if options[:identity]
+        Fields::Standard.new(field_name, opts)
+      end
+
+      def get_field_type(field_name, raw_type)
+        type = raw_type ? Fields::FieldTypes.get(raw_type) : Object
+        raise Mongoid::Errors::UnknownFieldType.new(self.name, field_name, raw_type) unless type
+        warn_unsupported_bson_type(type)
+        type
       end
 
       def warn_unsupported_bson_type(type)

lib/mongoid/fields/field_types.rb

@@ -53,8 +53,6 @@ def get(field_type)
             module_field_type(field_type)
           when Symbol, String
             mapping[field_type]
-          else
-            raise Mongoid::Errors::UnknownFieldType.new(self.name, field, field_type)
           end
         end
 

spec/mongoid/fields/field_types_spec.rb

@@ -85,8 +85,8 @@
     context 'when value is nil' do
       let(:type) { nil }
 
-      it 'returns Object type' do
-        is_expected.to eq Object
+      it 'returns nil' do
+        is_expected.to eq nil
       end
     end
   end