While you have a point, you seem to miss the original problem of browser frameworks. Browsers work _differently_. This is not the problem of a framework. Moreover nothing can stop you from using node.js + DOM mock to test anything you want. Unfortunately most of these tests will stay useless. So it's not about a possibility to write them. It's about a sense.

And btw, we are going to implement node.js tests to use Travis very soon.