Object.prototype.assign polyfill for phantom.js based on https://github.com/tom-james-watson/phantomjs-polyfill and https://github.com/ptim/phantomjs-polyfill-find
This is a polyfill for Object.prototype.assign which is missing from PhantomJS.
npm install --save-dev phantomjs-polyfill-object-assign
Include the polyfill directly in the files list of your karma.conf
...
files: [
'./node_modules/phantomjs-polyfill-object-assign/object-assign-polyfill.js',
...
]
...