What is karma?
Karma is a test runner for JavaScript that runs on Node.js. It is designed to work with any testing framework and has plugins for many popular frameworks. Karma runs tests in real browsers, can watch file changes, and re-run tests during development. It is often used for unit testing and can be integrated with continuous integration tools.
What are karma's main functionalities?
Running tests in real browsers
This code configures Karma to run tests in both Chrome and Firefox browsers using the Jasmine testing framework. The 'files' property specifies the location of the test files.
module.exports = function(config) {
config.set({
browsers: ['Chrome', 'Firefox'],
frameworks: ['jasmine'],
files: ['test/**/*.js']
});
};
Watching files and re-running tests
This configuration enables Karma's file watching feature. When set to true, Karma will watch for any file changes and automatically re-run the tests, which is useful during development.
module.exports = function(config) {
config.set({
autoWatch: true,
singleRun: false
});
};
Integration with continuous integration tools
This configuration is set up for continuous integration environments. It runs the tests a single time and uses reporters to output test results, such as the JUnit reporter which outputs results in an XML format that can be consumed by CI tools.
module.exports = function(config) {
config.set({
singleRun: true,
reporters: ['progress', 'junit'],
junitReporter: {
outputFile: 'test-results.xml'
}
});
};
Other packages similar to karma
mocha
Mocha is a feature-rich JavaScript test framework running on Node.js, making asynchronous testing simple. It is often compared to Karma, but unlike Karma, Mocha does not run tests in real browsers and does not have a built-in watcher.
jest
Jest is a delightful JavaScript Testing Framework with a focus on simplicity. It works out of the box for any React project. Jest runs tests in a Node environment instead of real browsers, provides a powerful mocking library, and has a built-in test runner and assertion library.
jasmine
Jasmine is a behavior-driven development framework for testing JavaScript code. It does not require a DOM, and it has a clean, obvious syntax so that you can easily write tests. Jasmine is often used as a testing framework within Karma, but it can also be used standalone.
Karma
A simple tool that allows you to execute JavaScript code in multiple
real browsers, powered by Node.js and Socket.io.
The main purpose of Karma is to make your TDD development easy,
fast, and fun.
When should I use Karma?
- You want to test code in real browsers.
- You want to test code in multiple browsers (desktop, mobile,
tablets, etc.).
- You want to execute your tests locally during development.
- You want to execute your tests on a continuous integration server.
- You want to execute your tests on every save.
- You love your terminal.
- You don't want your (testing) life to suck.
- You want to use Istanbul to automagically generate coverage
reports.
- You want to use RequireJS for your source files.
But I still want to use _insert testing library_
Karma is not a testing framework, neither an assertion library,
so for that you can use pretty much anything you like. Right now out
of the box there is support for
- Mocha
- Jasmine
- QUnit
- _anything else_ Write your own adapter. It's not that hard. And we
are here to help.
Which Browsers can I use?
All the major browsers are supported, if you want to know more see the
Browsers page.
Troubleshooting
My tests are running really slow
-
If you're testing in the browser, make sure the Karma tab is the active tab. If you're using LiveReload to develop, try opening a second browser window so Karma can always be active.
-
Make sure you're not watching too many files. Set your logLevel
to config.LOG_DEBUG
to see how many files are being watched.
I want to use it. Where do I sign?
You don't need to sign anything but here are some resources to help
you to get started. And if you need even more infos have a look at our
great website.
Obligatory Screencast.
Every serious project has a screencast, so here is ours. Just click
here and let the show begin.
NPM Installation.
If you have Node.js installed, it's as simple as
$ npm install -g karma
This will give you the latest stable version available on npm. If you
want to live life on the edge you can do so by
$ npm install -g karma@canary
The curious can have a look at the documentation articles for
[Getting Started] and Versioning.
Using it.
Go into your project and create a Karma configuration. That is
just a simple JavaScript or CoffeeScript file that tells Karma
where all the awesomeness of your project are.
You can find a simple example in
test/client/karma.conf.js
which contains most of the options.
To create your own from scratch there is the init
command, which
will be named karma.conf.js
by default:
$ karma init
This will ask you many questions and if you answered them all correct
you will be allowed to use Karma.
For more information on the configuration options see
Configuration File Overview.
Now that you have your configuration all that is left to do is to
start Karma:
$ karma start
If you want to run tests manually (without auto watching file changes), you can:
$ karma run
But only if you have started the Karma server before.
Why did you create this?
Throughout the development of AngularJS, we've been using JSTD for
testing. I really think that JSTD is a great idea. Unfortunately, we
had many problems with JSTD, so we decided to write our own test
runner based on the same idea. We wanted a simple tool just for
executing JavaScript tests that is both stable and fast. That's why we
use the awesome Socket.io library and Node.js.
I still don't get it. Where can I get help?
This is so great. I want to help.
See
Contributing.md
or the docs for more information.
My boss wants a license. So where is it?
The MIT License
Copyright (C) 2011-2013 Vojta Jína.
Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation files
(the "Software"), to deal in the Software without restriction,
including without limitation the rights to use, copy, modify, merge,
publish, distribute, sublicense, and/or sell copies of the Software,
and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.