This video is an introduction to Karma, an open source test runner that makes testing JavaScript applications in real browsers frictionless and enjoyable.
Testing is not optional when one is building a JavaScript application that must work across many browsers and devices. However executing tests in all of these various environments is hard. Karma turns this typically painstaking task into a piece of cake. It allows you to execute JavaScript tests in real browsers or devices such as your phone or tablet directly from the comfort of your terminal or your favorite IDE.
Further references
Karma Home Page: http://karma-runner.github.io/
Karma presentation: http://www.methodsandtools.com/tools/karma.php