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JavaScript unit test tools for TDD (9)

I've looked into and considered many JavaScript unit tests and testing tools, but have been unable to find a suitable option to remain fully TDD compliant. So, is there a JavaScript unit test tool that is fully TDD compliant?


There is also BusterJS from Christian Johansen, the author of Test Driven Javascript Development and the Sinon framework. From the site:

Buster.JS is a new JavaScript testing framework. It does browser testing by automating test runs in actual browsers (think JsTestDriver), as well as Node.js testing.

Karma or Protractor

Karma is a JavaScript test-runner built with Node.js and meant for unit testing.

The Protractor is for end-to-end testing and uses Selenium Web Driver to drive tests.

Both have been made by the Angular team. You can use any assertion-library you want with either.

Screencast: Karma Getting started



  • Uses node.js, so compatible with Win/OS X/Linux
  • Run tests from browser or headless with PhantomJS
  • Run on multiple clients at once
  • Option to launch, capture, and automatically shutdown browsers
  • Option to run server/clients on development computer or separately
  • Run tests from command line (can be integrated into ant/maven)
  • Write tests xUnit or BDD style
  • Supports multiple JavaScript test frameworks
  • Auto-run tests on save
  • Proxies requests cross-domain
  • Possible to customize:
    • Extend it to wrap other test-frameworks (Jasmine, Mocha, QUnit built-in)
    • Your own assertions/refutes
    • Reporters
    • Browser Launchers
  • Plugin for WebStorm
  • Supported by Netbeans IDE


  • Does not support NodeJS (i.e. backend) testing
  • No plugin for Eclipse (yet)
  • No history of previous test results


I'm totally unqualified to comment on mocha.js's features, strengths, and weaknesses, but it was just recommended to me by someone I trust in the JS community.

List of features, as reported by its web site:

  • browser support
  • simple async support, including promises
  • test coverage reporting
  • string diff support
  • javascript # API for running tests
  • proper exit status for CI support etc
  • auto-detects and disables coloring for non-ttys
  • maps uncaught exceptions to the correct test case
  • async test timeout support
  • test-specific timeouts
  • growl notification support
  • reports test durations
  • highlights slow tests
  • file watcher support
  • global variable leak detection
  • optionally run tests that match a regexp
  • auto-exit to prevent "hanging" with an active loop
  • easily meta-generate suites & test-cases
  • mocha.opts file support
  • clickable suite titles to filter test execution
  • node debugger support
  • detects multiple calls to done()
  • use any assertion library you want
  • extensible reporting, bundled with 9+ reporters
  • extensible test DSLs or "interfaces"
  • before, after, before each, after each hook
  • arbitrary transpiler support (coffee-script etc)
  • TextMate bundle


This no longer exists, redirects to sequential.js instead

Yolpo is a tool to visualize the execution of javascript. Javascript API developers are encouraged to write their use cases to show and tell their api. Such use cases forms the basis of regression tests.


Futuristic test runner with built-in support for ES2015. Even though JavaScript is single-threaded, IO in Node.js can happen in parallel due to its async nature. AVA takes advantage of this and runs your tests concurrently, which is especially beneficial for IO heavy tests. In addition, test files are run in parallel as separate processes, giving you even better performance and an isolated environment for each test file.

  • Minimal and fast
  • Simple test syntax
  • Runs tests concurrently
  • Enforces writing atomic tests
  • No implicit globals
  • Isolated environment for each test file
  • Write your tests in ES2015
  • Promise support
  • Generator function support
  • Async function support
  • Observable support
  • Enhanced asserts
  • Optional TAP o utput
  • Clean stack traces


A JavaScript test-runner built with Node.js. Very modular and flexible. It comes with its own assertion library, but you can add your own if you like. The assertions library is decoupled, so you can also use it with other test-runners. Instead of using assert(!...) or expect(...).not..., it uses refute(...) which is a nice twist imho.

A browser JavaScript testing toolkit. It does browser testing with browser automation (think JsTestDriver), qunit style static HTML page testing, testing in headless browsers (phantomjs, jsdom, ...), and more. Take a look at the overview!

A Node.js testing toolkit. You get the same test case library, assertion library, etc. This is also great for hybrid browser and Node.js code. Write your test case with Buster.JS and run it both in Node.js and in a real browser.

Screencast: Buster.js Getting started (2:45)


  • Uses node.js, so compatible with Win/OS X/Linux
  • Run tests from browser or headless with PhantomJS (soon)
  • Run on multiple clients at once
  • Supports NodeJS testing
  • Don't need to run server/clients on development computer (no need for IE)
  • Run tests from command line (can be integrated into ant/maven)
  • Write tests xUnit or BDD style
  • Supports multiple JavaScript test frameworks
  • Defer tests instead of commenting them out
  • SinonJS built in
  • Auto-run tests on save
  • Proxies requests cross-domain
  • Possible to customize:
    • Extend it to wrap other test-frameworks (JsTestDriver built in)
    • Your own assertions/refutes
    • Reporters (xunit XML, traditional dots, specification, tap, teamcity and more built in)
    • Customize/replace the HTML that is used to run the browser-tests
  • TextMate and Emacs integration


  • Stil in beta so can be buggy
  • No plugin for Eclipse/IntelliJ (yet)
  • Doesn't group results by os/browser/version like TestSwarm *. It does, however, print out the browser name and version in the test results.
  • No history of previous test results like TestSwarm *
  • Doesn't fully work on windows as of May 2014

* TestSwarm is also a Continuous Integration server, while you need a separate CI server for Buster.js. It does, however, output xUnit XML reports, so it should be easy to integrate with Hudson, Bamboo or other CI servers.


TestSwarm is officially no longer under active development as stated on their GitHub webpage. They recommend Karma, browserstack-runner, or Intern.


This is a client-side test-runner that might interest developers familiar with Ruby or Ruby on Rails. The syntax is based on RSpec that's used for testing in Rails projects.

Jasmine is a behavior-driven development framework for testing your JavaScript code. It does not depend on any other JavaScript frameworks. It does not require a DOM.

If you have experience with this test-runner, please contribute with more info :)

Project home:


QUnit focuses on testing JavaScript in the browser while providing as much convenience to the developer as possible. Blurb from the site:

QUnit is a powerful, easy-to-use JavaScript unit test suite. It's used by the jQuery, jQuery UI and jQuery Mobile projects and is capable of testing any generic JavaScript code

QUnit shares some history with TestSwarm (above):

QUnit was originally developed by John Resig as part of jQuery. In 2008 it got its own home, name and API documentation, allowing others to use it for their unit testing as well. At the time it still depended on jQuery. A rewrite in 2009 fixed that, now QUnit runs completely standalone. QUnit's assertion methods follow the CommonJS Unit Testing specification, which was to some degree influenced by QUnit.

Project home:


Another great tool is sinon.js by Christian Johansen, the author of Test-Driven JavaScript Development. Best described by himself:

Standalone test spies, stubs and mocks for JavaScript. No dependencies works with any unit testing framework.


The Intern Web site provides a direct feature comparison to the other testing frameworks on this list. It offers more features out of the box than any other JavaScript-based testing system.


A new but yet very powerful testing framework. It allows snapshot based testing as well this increases the testing speed and creates a new dynamic in terms of testing

Check out one of their talks:

Better yet: Getting Started


JavaScript testing framework released by Google:

  • Extremely fast test startup and execution time, without having to run a browser.
  • Clean, readable output in the case of both passing and failing tests.
  • A browser-based test runner that can simply be refreshed whenever JS is changed.
  • Style and semantics that resemble Google Test for C++.
  • A built-in mocking framework that requires minimal boilerplate code (e.g. no $tearDown or $verifyAll) with style and semantics based on the Google C++ Mocking Framework.

There are currently no binaries for Windows

The JavaScript section of the Wikipedia entry, List of Unit Testing Frameworks, provides a list of available choices. It indicates whether they work client-side, server-side, or both.

We added JUnit integration to our Java to Javascript code generator ST-JS ( The framework generates to corresponding Javascript for both the tested code and the unit tests and sends the code to different browsers.

There is no need for a separate server as the unit test runner opens the needed http port (and closes it once the tests finished). The framework manipulates the Java stacktrace so that the failed asserts are correctly displayed by the JUnit Eclipse plugin. Here is a simple example with jQuery and Mockjax:

@HTMLFixture("<div id='fortune'></div>")

@Scripts({ "classpath://jquery.js",
       "classpath://jquery.mockjax.js", "classpath://json2.js" })
public class MockjaxExampleTest {
  public void myTest() {
    $.ajaxSetup($map("async", false));
    $.mockjax(new MockjaxOptions() {
        url = "/restful/fortune";
        responseText = new Fortune() {
            status = "success";
            fortune = "Are you a turtle?";

    $.getJSON("/restful/fortune", null, new Callback3<Fortune, String, JQueryXHR>() {
      public void $invoke(Fortune response, String p2, JQueryXHR p3) {
        if (response.status.equals("success")) {
          $("#fortune").html("Your fortune is: " + response.fortune);
        } else {
          $("#fortune").html("Things do not look good, no fortune was told");

    assertEquals("Your fortune is: Are you a turtle?", $("#fortune").html());

  private static class Fortune {
    public String status;
    public String fortune;

YUI has a testing framework as well. This video from Yahoo! Theater is a nice introduction, although there are a lot of basics about TDD up front.

This framework is generic and can be run against any JavaScript or JS library.

You have "runs on actual browser" as a pro, but in my experience that is a con because it is slow. But what makes it valuable is the lack of sufficient JS emulation from the non-browser alternatives. It could be that if your JS is complex enough that only an in browser test will suffice, but there are a couple more options to consider:

HtmlUnit: "It has fairly good JavaScript support (which is constantly improving) and is able to work even with quite complex AJAX libraries, simulating either Firefox or Internet Explorer depending on the configuration you want to use." If its emulation is good enough for your use then it will be much faster than driving a browser.

But maybe HtmlUnit has good enough JS support but you don't like Java? Then maybe:

Celerity: Watir API running on JRuby backed by HtmlUnit.

or similarly

Schnell: another JRuby wrapper of HtmlUnit.

Of course if HtmlUnit isn't good enough and you have to drive a browser then you might consider Watir to drive your JS.

You should have a look at env.js. See my blog for an example how to write unit tests with env.js.