Hello I am professional JS developer since 2012 and pretty much all of the projects i've worked on required unit testing. In order to show you that I know my stuff let me tell you that karma is just the test runner but there are different libraries to use for the tests themselves. Those would be Jasmin, Chai, Sinon and other. I would like to talk to to you about the volume of the code that needs to be covered and what test case coverage you're aiming for. (Usually aiming for 100% is waste of time and money) Please write me a message if you interested. I'd love to help you on that one.
Regards,
Emiliyan