My setup is karma along with karma-webpack plugin, mocha, sinon, chai and sinon-chai and launching Chrome. The tests run fine with normal testing but I cannot debug. When I debug using the karma runner, it launches Parallels (on mac) instead. I have also tried Running Karma, and then using a JS Debug runner instead. The JS Debug runner also launches parallels instead.
I also notice that when running Chrome with Karma, plugins are not included so I'm not sure how Webstorm can debug tests with Karma if the browser is not including in the Jetbrains debugging plugin for Chrome.