karma.conf.js

module.exports = function (config) {
	config.set({
		// Frameworks to use
		// available frameworks: https://npmjs.org/browse/keyword/karma-adapter
		frameworks: ['browserify', 'mocha'],

		// List of files / patterns to load in the browser
		files: [
			'src/browser.js',
			'src/common.js',
			'test.js'
		],

		// Test results reporter to use
		// possible values: 'dots', 'progress'
		// available reporters: https://npmjs.org/browse/keyword/karma-reporter
		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_DEBUG,

		// Start these browsers
		// available browser launchers: https://npmjs.org/browse/keyword/karma-launcher
		browsers: ['HeadlessChrome'],
		customLaunchers: {
			HeadlessChrome: {
				base: 'ChromeHeadless',
				flags: ['--no-sandbox']
			}
		},

		preprocessors: {
			// *Sigh* what a glob, folks!
			'{{!(node_modules),*.js},!(node_modules)/**/*.js}': ['browserify']
		},

		browserify: {
			debug: true,
			transform: ['brfs']
		},

		// 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: 1
	});
};