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Karma Plus Sauce

Run your unit tests on Sauce Labs' browser cloud!


Install karma-sauce-launcher as a devDependency in your package.json:

npm install karma-sauce-launcher --save-dev


This launcher is typically used in CI to run your unit tests across many browsers and platforms on Sauce Labs. However, you can also use it locally to debug tests in browsers not available on your machine. It is expected that you are already familiar with Karma when configuring this launcher, so if you are new to Karma, head over to the Karma website.

The Sauce Labs platform configurator can help to find the correct configuration for your desired test platform.

Adding karma-sauce-launcher to an existing Karma config

To configure this launcher, you need to add two properties to your top-level Karma config, sauceLabs and customLaunchers, set the browsers array to use Sauce Labs browsers, and add the sauceLabs reporter.

The sauceLabs object defines global properties for each browser/platform while the customLaunchers object configures individual browsers. The sauceLabs reporter allows your tests results to be properly displayed on https://saucelabs.com. Here is a sample Karma config to get the launcher running:

module.exports = function(config) {
  // Example set of browsers to run on Sauce Labs
  // Check out https://saucelabs.com/platforms for all browser/platform combos
  var customLaunchers = {
    sl_chrome: {
      base: 'SauceLabs',
      browserName: 'chrome',
      platform: 'Windows 7',
      version: '35'
    sl_firefox: {
      base: 'SauceLabs',
      browserName: 'firefox',
      version: '30'
    sl_ios_safari: {
      base: 'SauceLabs',
      browserName: 'iphone',
      platform: 'OS X 10.9',
      version: '7.1'
    sl_ie_11: {
      base: 'SauceLabs',
      browserName: 'internet explorer',
      platform: 'Windows 8.1',
      version: '11'
    sl_android: {
      base: 'SauceLabs',
      browserName: 'Browser',
      platform: 'Android',
      version: '4.4',
      deviceName: 'Samsung Galaxy S3 Emulator',
      deviceOrientation: 'portrait'
    // The rest of your karma config is here
    // ...
    sauceLabs: {
        testName: 'Web App Unit Tests'
    customLaunchers: customLaunchers,
    browsers: Object.keys(customLaunchers),
    reporters: ['dots', 'saucelabs'],
    singleRun: true

Note: this config assumes that process.env.SAUCE_USERNAME and process.env.SAUCE_ACCESS_KEY are set.

Example karma-sauce-launcher configs

For example configs using this launcher (using Travis CI), check out this repo's karma file, the karma-sauce-example repo (which demonstrates how to use Sauce locally), or AngularJS' Karma config.

sauceLabs config properties shared across all browsers


Type: String Default: process.env.SAUCE_USERNAME

Your Sauce Labs username (if you don't have an account, you can sign up here).


Type: String Default: process.env.SAUCE_ACCESS_KEY

Your Sauce Labs access key which you will see on your account page.


Type: String

Proxy for connecting to Sauce REST API, which is used to communicate job updates of pass/fail.


Type: Boolean Default: true

If true, Sauce Connect will be started automatically. Set this to false if you are launching tests locally and want to start Sauce Connect via a binary or the Mac app in the background to improve test speed.


Type: Object Default:

  username: 'yourUsername',
  accessKey: 'yourAccessKey',
  tunnelIdentifier: 'autoGeneratedTunnelID'

Options to send to Sauce Connect. Check here for all available options.


Type: String default: ondemand.saucelabs.com

If set, will attempt to connect to the specified host as a Selenium relay. This is intended to send Selenium commands through a Sauce Connect tunnel.


Type: Integer Default: 80

If set, will change the host used to connect to the Selenium server. This is intended to send Selenium commands through a Sauce Connect tunnel.


Type: String Default: One of the following environment variables: process.env.BUILD_NUMBER process.env.BUILD_TAG process.env.CI_BUILD_NUMBER process.env.CI_BUILD_TAG process.env.TRAVIS_BUILD_NUMBER process.env.CIRCLE_BUILD_NUM process.env.DRONE_BUILD_NUMBER

ID of the build currently running. This should be set by your CI.


Type: String Default: 'Karma test'

Name of the unit test group you are running.


Type: String

Sauce Connect can proxy multiple sessions, this is an id of a session.


Type: Array of Strings

Tags to use for filtering jobs in your Sauce Labs account.


Type: Boolean Default: false

Set to true if you want to record a video of your Karma session.


Type: Boolean Default: true

Set to false if you don't want to record screenshots.


Type: String Default: null

Control who can view job details. Available visibility levels are documented on the SauceLabs website.


Type: Object Default: {}

Send arbitrary data alongside your tests. See the SauceLabs documentation for more details.

customLaunchers config properties

The customLaunchers object has browser names as keys and configs as values. Documented below are the different properties which you can configure for each browser/platform combo.

Note: You can learn about the available browser/platform combos on the Sauce Labs platforms page, platforms configurator page and REST API page.


Type: String Required: true

This defines the base configuration for the launcher. In this case it should always be SauceLabs so that browsers can use the base Sauce Labs config defined at the root sauceLabs property.


Type: String Required: true

Name of the browser.


Type: String Default: Latest browser version for all browsers except Chrome which defaults to '27'

Version of the browser to use.


Type: String Default: 'Linux' for Firefox/Chrome, 'Windows 7' for IE/Safari

Name of platform to run browser on.


Type: String Default: 'portrait'

Accepted values: 'portrait' || 'landscape'

Set this string if your unit tests need to run on a particular mobile device orientation for Android Browser or iOS Safari.

Behind the scenes

This launcher uses Sauce Connect in the background. If you are interested in security or want to see the system requirements, head over to the documentation.

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