karma.conf.js

const webpackConfig = require('./webpack.config');

module.exports = (config) => {
	config.set({
		// Base path that will be used to resolve all patterns (eg. files, exclude).
		basePath: './',

		// Frameworks to use.
		// Available frameworks: https://npmjs.org/browse/keyword/karma-adapter.
		frameworks: ['mocha', 'chai', 'sinon', 'webpack'],

		// List of files / patterns to load in the browser.
		files: [
			'tests/test.js',
			{ pattern: 'tests/mocks/*.js', included: false, served: true }
		],

		// Preprocess matching files before serving them to the browser.
		// Available preprocessors: https://npmjs.org/browse/keyword/karma-preprocessor.
		preprocessors: {
			// Add webpack as preprocessor.
			'tests/test.js': ['webpack', 'sourcemap'],
		},

		webpack: webpackConfig,

		webpackMiddleware: {
			// Webpack-dev-middleware configuration.
			noInfo: true
		},

		// List of files / patterns to exclude.
		exclude: [],

		// Test results reporter to use. Possible values: 'dots', 'progress'.
		// Available reporters: https://npmjs.org/browse/keyword/karma-reporter.
		reporters: ['mocha'],

		// 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: https://npmjs.org/browse/keyword/karma-launcher.
		browsers: ['Chrome'],

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

		// Concurrency level.
		// How many browser should be started simultaneous.
		concurrency: Infinity
	});
};