Always disable root element key for child entities

If you expose :children, :using => ChildEntity,
child entities will not be wrapped in a Hash with
a root key, even if this is configured as a default
for the ChildEntity class.

Author: Jon Evans

lib/grape/entity.rb

@@ -195,7 +195,7 @@ def value_for(attribute, options = {})
       if exposure_options[:proc]
         exposure_options[:proc].call(object, options)
       elsif exposure_options[:using]
-        exposure_options[:using].represent(object.send(attribute))
+        exposure_options[:using].represent(object.send(attribute), :root => nil)
       else
         object.send(attribute)
       end

spec/grape/entity_spec.rb

@@ -211,6 +211,21 @@
         rep.last.serializable_hash[:name].should == 'Friend 2'
       end
 
+      it 'should disable root key name for child representations' do
+        class FriendEntity < Grape::Entity
+          root 'friends', 'friend'
+          expose :name, :email
+        end
+        fresh_class.class_eval do
+          expose :friends, :using => FriendEntity
+        end
+        rep = subject.send(:value_for, :friends)
+        rep.should be_kind_of(Array)
+        rep.reject{|r| r.is_a?(FriendEntity)}.should be_empty
+        rep.first.serializable_hash[:name].should == 'Friend 1'
+        rep.last.serializable_hash[:name].should == 'Friend 2'
+      end
+
       it 'should call through to the proc if there is one' do
         subject.send(:value_for, :computed, :awesome => 123).should == 123
       end