we could simplify this one to:

```js
  it('should not clone objects returned from functions', function () {
    var obj = {};
    var Thing = model('thing')
      .use(defaults)
      .attr('custom', { default: function() {
        return obj;
      }});

    var thing = new Thing();
    assert('object' === type(thing.custom()));
    assert(obj === thing.custom());
  });
```

and just check to see if its the same object