How do you unit test your javascript

Question

I spend a lot of time working in javascript of late. I have not found a way that seems to work well for testing javascript. This in the past hasn't been a problem for me since most of the websites I worked on had very little javascript in them. I now have a new website that makes extensive use of jQuery I would like to build unit tests for most of the system.

My problems are this.

• Most of the functions make changes to the DOM in some way.
• Most of the functions request data from the web server as well and require a session on the service to get results back.

I would like to run the test from either a command line or a test running harness rather then in a browser.

Any help or articles I should be reading would be helpful.

• Paul Sanwald: Have a look at JSTestDriver, written by Misko Hevery, who writes a lot of great articles on testability in general.

Answer 1

Maybe QUnit could help you. It is the official test suite of the jQuery project. As described in the documentation, tests can also be run outside of a browser (with Rhino for instance).

Answer 2

Because of the interactive nature of Javascript, it's hard to write unit-tests to anything but libraries. To test interactions, we use Selenium which allows you to record interactions and check for expected outcome (such as a DIV appearing or a value changing). Tests can be grouped into suites and ran automatically.

Selenium tests can also be run on the server without a browser with some additional setup.