karma.conf.js

require('babel-polyfill')
var argv = require('yargs').argv;
var path = require('path');

module.exports = function (config) {
    config.set({
        browsers: ['PhantomJS'],
        singleRun: !argv.watch, // just run once by default
        frameworks: ['mocha', 'chai'],
        // npm i karma-spec-reporter --save-dev
        // displays tests in a nice readable format
        reporters: ['spec'],

        // include some polyfills for babel and phantomjs
        files: [
            'node_modules/babel-polyfill/dist/polyfill.js',
            './node_modules/phantomjs-polyfill/bind-polyfill.js',
            './test/**/*.js', // specify files to watch for tests
            './test/**/*.tsx' // specify files to watch for tests
        ],
        preprocessors: {
            // these files we want to be precompiled with webpack
            // also run tests throug sourcemap for easier debugging
            ['./test/**/*.js']: ['webpack', 'sourcemap']
        },
        webpack: {
            devtool: 'inline-source-map',
            resolve: {
                // allow us to import components in tests like:
                // import Example from 'components/Example';
                root: path.resolve(__dirname, './src'),

                // allow us to avoid including extension name
                extensions: ['', '.js', '.jsx', '.ts', '.tsx', '.less'],

                // required for enzyme to work properly
                alias: {
                    'sinon': 'sinon/pkg/sinon'
                }
            },
            module: {
                // don't run babel-loader through the sinon module
                noParse: [
                    /node_modules\/sinon\//
                ],
                // run babel loader for our tests
                loaders: [
                    {test: /\.(js|jsx)$/, exclude: /node_modules/, loader: 'babel'},
                    {test: /\.(ts|tsx)$/, exclude: /node_modules/, loader: "ts-loader"},
                    {test: /\.less$/, exclude: /node_modules/, loader: "style!css!less"}],
            },
            // required for enzyme to work properly
            externals: {
                'jsdom': 'window',
                'cheerio': 'window',
                'react/lib/ExecutionEnvironment': true,
                'react/lib/ReactContext': 'window'
            },
        },
        webpackMiddleware: {
            noInfo: true
        },
        // tell karma all the plugins we're going to be using
        plugins: [
            'karma-mocha',
            'karma-chai',
            'karma-webpack',
            'karma-phantomjs-launcher',
            'karma-spec-reporter',
            'karma-sourcemap-loader'
        ]
    });
};