Fixing `as_json` method for ActiveRecord models.

When you've got an AR Model and you override the `as_json` method,
you should be able to add default options to the renderer, like this:

    class User < ActiveRecord::Base
      def as_json(options = {})
        super(options.merge(:except => [:password_digest]))
      end
    end

This was not possible before this commit. See the added test case.

1 files changed, 10 insertions, 0 deletions

diff --git a/activemodel/test/cases/serializers/json_serialization_test.rb b/activemodel/test/cases/serializers/json_serialization_test.rb
index 40fdcf20ca..a754d610b9 100644
--- a/activemodel/test/cases/serializers/json_serialization_test.rb
+++ b/activemodel/test/cases/serializers/json_serialization_test.rb
@@ -206,4 +206,14 @@ class JsonSerializationTest < ActiveModel::TestCase
     assert_no_match %r{"preferences":}, json
   end
 
+  test "custom as_json options should be extendible" do
+    def @contact.as_json(options = {}); super(options.merge(:only => [:name])); end
+    json = @contact.to_json
+
+    assert_match %r{"name":"Konata Izumi"}, json
+    assert_no_match %r{"created_at":#{ActiveSupport::JSON.encode(Time.utc(2006, 8, 1))}}, json
+    assert_no_match %r{"awesome":}, json
+    assert_no_match %r{"preferences":}, json
+  end
+
 end