If no Karma test seems to work in Foundation for Apps ...
Have a look at the exception stack and see if you can find some reference to "mqInitRun" and "Cannot read property 'replace' of null" in there. This is a hint, that the test config may need a valid CSS.
To solve this, just add your app.css at the top of the file list in your karma.conf.js and you should be good to go.