ERROR [karma]: TypeError: Path must be a string. Received undefined
    at assertPath (path.js:7:11)
    at Object.extname (path.js:887:5)
    at d:\Test\test-karma\node_modules\.1.6.0@karma\lib\middleware\karma.js:181:32
    at d:\Test\test-karma\node_modules\.1.6.0@karma\lib\middleware\common.js:117:36
    at d:\Test\test-karma\node_modules\.4.1.11@graceful-fs\graceful-fs.js:78:16
    at FSReqWrap.readFileAfterClose [as oncomplete] (fs.js:439:3)

module.exports = function (config) {
    config.set({
        browsers: ['PhantomJS'],
        files: [
            './test.js'
        ],
        singleRun: true,
        // coverage reporter generates the coverage
        reporters: ['progress'],
        plugins: [
            'karma-mocha',
            'karma-phantomjs-launcher'
        ]
    });
};

var Karma = require('karma').Server;
var path = require('path');
var fn = Array.prototype.indexOf;
delete Array.prototype['indexOf'];
Array.prototype['indexOf'] = function () {
    return fn.apply(this, arguments);
};
new Karma({
    configFile: path.resolve(__dirname, 'karma.conf.js')
}).start();

for (var i in files.included)