Also, sort of wondering about do we explicitly test that our real serializers hook into action controller, where check for our various serializers. Did you look into undefining the XHTMLSerializer class with something like:

```ruby
Object.send(:remove_const, Crichton::Serializers::XHTMLSerializer) 
require 'xhtmlserializer`
```

I waffled the exact syntax, but you could check that. Seems somewhere we should check that we get things working with :html, :xhtml and whatever in the future working with to_media_type. Thoughts?