include babel-polyfill

karma.conf.js

@@ -79,7 +79,7 @@ module.exports = function(config) {
 
     // start these browsers
     // available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
-    browsers: [ envConfig.isCI ? 'PhantomJS' : envConfig.devBrowser ],
+    browsers: [ envConfig.isCI ? 'ChromeTravisCI' : envConfig.devBrowser ],
     customLaunchers: {
       ChromeTravisCI: {
         base: 'Chrome',

package.json

@@ -8,6 +8,7 @@
     "babel-core": "^6.1.21",
     "babel-eslint": "^4.1.5",
     "babel-loader": "^6.1.0",
+    "babel-polyfill": "^6.2.0",
     "babel-preset-es2015": "^6.1.18",
     "codemirror": "^5.8.0",
     "coveralls": "^2.11.4",
@@ -23,8 +24,10 @@
     "karma-coverage": "^0.5.3",
     "karma-coveralls": "^1.1.2",
     "karma-jasmine": "^0.3.6",
+    "karma-phantomjs-launcher": "^0.2.1",
     "karma-sourcemap-loader": "^0.3.6",
     "karma-webpack": "^1.7.0",
+    "phantomjs": "^1.9.19",
     "pretty-js": "^0.1.8",
     "style-loader": "^0.13.0",
     "webpack": "^1.12.6",

spec/index.js

@@ -1,3 +1,6 @@
+// *Some* environments (phantomjs) don't have es5 (Function.prototype.bind)
+require('babel-polyfill');
+
 // require all the files in the spec folder that end with -test.js
 var context = require.context('.', false, /.*-test.js$/);
 context.keys().forEach(context);