How to test django's front-end javascripts

I'm trying to test my django powered website's backbone.js front-end.

I found out that karma.js and jasmine are for those frontend testing, but it seems like they are just for "front-end", which means they cannot test interactions between front-end backbone models and my django REST API server.

What I'm looking for is an testing framework that can test front-end javascripts in a BDD style (including interactions between front-end and back-end).

Is there any sharp tools for that?