Take into account current time zone when serializing datetime values [#6096 state:resolved]

Signed-off-by: José Valim <jose.valim@gmail.com>

activemodel/lib/active_model/serializers/xml.rb

@@ -17,6 +17,7 @@ module ActiveModel
 
           def initialize(name, serializable, raw_value=nil)
             @name, @serializable = name, serializable
+            raw_value = raw_value.in_time_zone if raw_value.respond_to?(:in_time_zone)
             @value = raw_value || @serializable.send(name)
             @type  = compute_type
           end

activerecord/test/cases/xml_serialization_test.rb

@@ -4,6 +4,7 @@ require 'models/post'
 require 'models/author'
 require 'models/comment'
 require 'models/company_in_module'
+require 'models/toy'
 
 class XmlSerializationTest < ActiveRecord::TestCase
   def test_should_serialize_default_root
@@ -83,6 +84,26 @@ class DefaultXmlSerializationTest < ActiveRecord::TestCase
   end
 end
 
+class DefaultXmlSerializationTimezoneTest < ActiveRecord::TestCase
+  def test_should_serialize_datetime_with_timezone
+    timezone, Time.zone = Time.zone, "Pacific Time (US & Canada)"
+
+    toy = Toy.create(:name => 'Mickey', :updated_at => Time.utc(2006, 8, 1))
+    assert_match %r{<updated-at type=\"datetime\">2006-07-31T17:00:00-07:00</updated-at>}, toy.to_xml
+  ensure
+    Time.zone = timezone
+  end
+
+  def test_should_serialize_datetime_with_timezone_reloaded
+    timezone, Time.zone = Time.zone, "Pacific Time (US & Canada)"
+
+    toy = Toy.create(:name => 'Minnie', :updated_at => Time.utc(2006, 8, 1)).reload
+    assert_match %r{<updated-at type=\"datetime\">2006-07-31T17:00:00-07:00</updated-at>}, toy.to_xml
+  ensure
+    Time.zone = timezone
+  end
+end
+
 class NilXmlSerializationTest < ActiveRecord::TestCase
   def setup
     @xml = Contact.new.to_xml(:root => 'xml_contact')