This test:

    getJSON('/post/1', { data: data }).then(function(post) {
      equal(post.title, 'Rails is omasake', 'The requested data is present');
    });

In https://github.com/emberjs/ember.js/pull/3261/files#L6R131 ensure this.

And this is the implementation:

    _normalizeSuccessAjaxParams: function(data, textStatus, jqXHR) {    
      return data;
    }

Here https://github.com/emberjs/ember.js/pull/3261/files#L3R125