This code is from this blog posting http://www.syntaxsuccess.com/viewarticle/writing-jasmine-unit-tests-in-es6
Since code in the posting is outdated, I updated the codes to work with the latest babel modules.
git clone https://github.com/zirho/karma-es6-babel-webpack
cd karma-es6-babel-webpack
npm i
npm i -g karma-cli
npm run tests