Skip to main content

Karma Test Runner Integration With LambdaTest

Designed for rapid development, Karma testing framework is an open-source test runner for JavaScript that runs on Node.js. It was earlier termed as Testacular. Karma test runner increases web developers daily-basis productivity & ensures their web app stays more robust by offering quick and easy automated testing. Karma is highly favored in the web developer community due to its outstanding plugin support and integrations with numerous renowned CI packages such as Jenkins, Travis, and Semaphore. It is highly configurable to provide web developers a testing environment where they can receive feedback, instantly from their piece of code.

LambdaTest now integrates with Karma testing framework to boost your go-to market delivery. Perform automated cross browser testing with LambdaTest to ensure your development code renders seamlessly through an online Selenium Grid providing 3000+ real browsers running through machines, on cloud. Perform automation testing in parallel using LambdaTest’s Selenium Grid to drastically trim down your test cycles.


All the code samples in this documentation can be found in the Karma LambdaTest Repository on Image GitHub. You can either download or clone the repository to quickly run your tests.

In order to perform tests with LambdaTest using Karma testing framework, you would need the below things to be already set up:

1. Global Dependencies

  • Make sure to use the latest version of JavaScript.
  • A Git or GitHub repository
  • Download and install node.js and node package manager or npm. To install node.js with homebrew use the below command.

$ brew install node

  • If you have npm already installed, you may want to upgrade it to latest version. Here the code you can run in your terminal to upgrade npm.

npm install npm@latest -g

  • Install Angular CLI(Command Line Interface) with the below command.

$ npm install -g @angular/cli

2. LambdaTest Authentication Credentials

Be aware of your LambdaTest authentication credentials i.e. your LambdaTest username, access key and HubURL. You need to set them up as your environment variables. You can retrieve them from your LambdaTest automation dashboard by clicking on the key icon near the help button.

  • For Windows user:
  • For macOS/Linux user:

Getting Started With Karma Test Runner Installation By Creating A Sample Project

Clone the sample project from LambdaTest GitHub repository by using the below command in your cmd/terminal.

git clone && cd angular-karma-sample

Install the node.js dependencies and Karma CLI globally using the below command.

npm install -g karma-cli && npm install

Change Browsers & Framework For Sample Project: If you wish to add more browsers or change the framework to something other than the one used in our Sample project then you can do so by editing the browser array/ framework array in the karma.conf.js file.

Configuring LambdaTest tunnel To Run Karma Tests With LambdaTest

To help you perform cross browser testing of your locally stored web pages, LambdaTest provides an SSH(Secure Shell) tunnel connection with the name LambdaTest tunnel. With LambdaTest tunnel, you can execute a test your local Karma tests on cloud for performing automated cross browser testing on more than 2000 browsers offered by Selenium Grid on LambdaTest. So you make sure how well your changes look, even before your customers. Curious to know more about LambdaTest tunnel?

Follow our documentation on LambdaTest tunnel to know it all. OS specific instructions to download and setup tunnel binary can be found at the following links.

Download the binary file of:

Once, the tunnel is successfully set up. You can add the below code to your capabilities for testing internal servers on your network.

tunnel: true,

Integrating Your Karma Testing Framework With LambdaTest

To integrate Karma test runner with LambdaTest you need to set up LambdaTest authentication credentials (access key & username) as your environment variables in the karma.conf.js file.

Below is a sample config file for integrating Karma test runner with LambdaTest. You can use the sample file to test your own automation test suite by replacing the environment variables according to your need. All the code used for the demonstration of this topic can be find in our GitHub repository for Karma.

// Karma testing framework configuration file, see link for more information

module.exports = function(config) {
// Lambdatest grid hostname and port

var webdriverConfig = {
hostname: '',
port: 80
hostname: 'localhost', // hostname, where karma web server will run
port: 9876,
basePath: './',

frameworks: ['jasmine', '@angular-devkit/build-angular'],

plugins: [

client: {
clearContext: false

coverageIstanbulReporter: {
dir: require('path').join(__dirname, '../coverage/karma-sample'),
reports: ['html', 'lcovonly', 'text-summary'],
fixWebpackSourcePaths: true

captureTimeout: 600000,
retryLimit: 1,
browserDisconnectTimeout: 90000,
browserDisconnectTolerance: 1,
browserNoActivityTimeout: 90000,
reporters: ['progress', 'kjhtml'],
colors: true,
concurrency: 1,
logLevel: config.LOG_DEBUG,
browsers: ['chrome'],

customLaunchers: {
chrome: {
base: 'WebDriver',
config: webdriverConfig,
browserName: 'chrome',
platform: 'windows 10',
version: '71.0',
name: 'Karma With Heartbeat',
user: process.env.LT_USERNAME,
accessKey: process.env.LT_ACCESS_KEY,
pseudoActivityInterval: 5000 // 5000 ms heartbeat
singleRun: true,
autoWatch: true

After declaring the required environment variable, comes the time to execute your test using the below command.

karma start karma.conf.js

karma start karma.conf.js

If you wish to use Jenkins, then follow this documentation.

Parallel Testing

Parallel testing is one of the most in-demand feature of LambdaTest Selenium Grid. By parallel testing, you can run more than one test case, simultaneously. This means that, parallel testing would allow you to execute numerous automation test cases altogether. So you execute a single test scenario across different browsers or could run different test scenarios across the same browser but with different browser versions.

To perform parallel testing, navigate to sample project “angular-karma-sample” and run the below command.

$ ng test

Monitor and analyze your test result ont the LambdaTest Automation Dashboard.

Avoid Timeouts With psuedoActivityInterval

To make sure our machines are not hold for long due to some incorrect test, we have come up with a restriction on the number of seconds that our machine is kept reserved for you. In cases, where our servers fail to retrieve a request from your local machine for more than 90 seconds, then your tests are aborted from the queue with the error message related to Timeouts.

If you wish to avoid such timeouts, you need to make use of the below parameter:

customLaunchers: { chrome: {
pseudoActivityInterval: 5000 // 5000 ms heartbeat to avoid timeouts
} }

Note: psuedoActivityInterval is presented as a default parameter with a value set to 0. Make sure to provide a value more than 0 in order to avoid the timeouts.

Deploy your code in a reliable manner at scale using Karma test runner integration with LambdaTest, and ensure it looks robust across every browser to provide a seamless user experience to all your visitors. Happy Testing!