Yadda brings true BDD to JavaScript test frameworks such as Mocha, QUnit, Nodeunit and CasperJS. By true BDD we mean that the ordinary language (e.g. English) steps are mapped to code, as opposed to merely decorating it. This is important because decorative steps such as those used by Jasmine, Mocha and Vows, can fall out of date and are a form of duplication. If your code is easily readable you they offer little benefit beyond some nice reporting.