test service class using es6 in angular

I have a service class written in es6 for an angular application. It is requesting an api using http for data. Now I want to test the service through mocha and chai. Here is what service looks like:

"use strict";
const HTTP = new WeakMap();
class EventService{
    constructor($http, moment){
        HTTP.set(this, $http);
        this.$http = $http;
        this.url = 'http://test/api/events?';
        this.apiKey = '1234asd';
    }

    getEvents(){
        return this.$http({
            url: this.url + 'from=' + this.from + '&to=' +  this.to + '&apiKey=' + this.apiKey,
            method: "GET",
            crossDomain: true,
            headers: {
                'Content-Type': 'application/json; charset=utf-8'
            }
        });
    }
}


EventService.$inject = ['$http', 'moment'];

export default EventService;

Karma.conf.js:

module.exports = function(config) {
  config.set({

    // base path that will be used to resolve all patterns (eg. files, exclude)
    basePath: '',


    // frameworks to use
    // available frameworks: http://ift.tt/1ft83uu
    frameworks: ['mocha', 'chai'],


    // list of files / patterns to load in the browser
    files: [
      'node_modules/angular/angular.js',
      'node_modules/angular-mocks/angular-mocks.js',
      'node_modules/moment/moment.js',
      'node_modules/angular-moment/angular-moment.js',
      'lib/shared/services/events-service.js',
      'tests/*.js'
    ],


    // list of files to exclude
    exclude: [
    ],


    // preprocess matching files before serving them to the browser
    // available preprocessors: http://ift.tt/1gyw6MG
    preprocessors: {
    },


    // test results reporter to use
    // possible values: 'dots', 'progress'
    // available reporters: http://ift.tt/1ft83KQ
    reporters: ['progress'],


    // web server port
    port: 9876,


    // enable / disable colors in the output (reporters and logs)
    colors: true,


    // level of logging
    // possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
    logLevel: config.LOG_INFO,


    // enable / disable watching file and executing tests whenever any file changes
    autoWatch: true,


    // start these browsers
    // available browser launchers: http://ift.tt/1ft83KU
    browsers: ['Chrome'],


    // Continuous Integration mode
    // if true, Karma captures browsers, runs the tests and exits
    singleRun: false,

    // Concurrency level
    // how many browser should be started simultaneous
    concurrency: Infinity
  })
}

Now I am just trying to get the test suite up and running, however, I am getting the following error when I run karma start:

Uncaught SyntaxError: Unexpected token export
  at lib/shared/services/events-service.js

Which is at the export command of the service. Would I have to do some configuration changes to make this work?