This is the HTML Working Group's test suite for HTML, Canvas, and Microdata (and version — 5.0, 5.1, LS, etc.). It is maintained by the HTML Test Suite Task Force, which for all that it has "Task Force" in its name is really a bunch of cool froods.

Tests are under html (for the HTML specification), canvas (for the Canvas specification), and microdata (Surprise test! Which specification are these tests for?).

Inside the specification directories, the tree represents the sections of the respective documents, using the section IDs for directory names, with a maximum of three levels deep. So if you're looking for tests for "The History interface", they will be under html/browsers/history/the-history-interface/.

Various resources that tests depend on are in common, images, and fonts.

In order to function properly, tests need to be run from a web server that has testharness.js in /resources/.

In the vast majority of cases the only branch that you should need to care about is master. If you are contributing, that is where you are expected to make your changes, that's the reference against which to make pull requests.

There is another branch called CR. This is a strict subset of master that is limited to features that are found in the Candidate Recommendation version of the relevant specifications.

If you see other branches in the repository, you can generally safely ignore them. Please note that branches prefixed with temp/ are temporary branches and will get deleted at some point. So don't base any work off them unless you want to see your work destroyed.

Save the Web, Write Some Tests!

Let's get the legalese out of the way:

All contributors must agree to the following W3C test licences:

• http://www.w3.org/Consortium/Legal/2008/04-testsuite-license.html
• http://www.w3.org/Consortium/Legal/2008/03-bsd-license.html

We can accept tests contributed under compatible conditions, just contact us to ask about it.

Legalese over.

Absolutely everyone is welcome (and even encouraged) to contribute to test development, so long as you fulfil the contribution requirements detailed above. No test is too small or too simple, especially if it corresponds to something for which you've noted an interoperability bug in a browser.

The way to contribute is just as usual: fork this repository (and make sure you're still relatively in sync with it if you forked a while ago), make your changes, and send in a pull request based on those. Please make your pull requests either to master, or to a feature/* branch (not to CR).

We can sometimes take a little while to go through pull requests because we have to go through all the tests and ensure that they match the specification correctly. But we look at all of them, and take everything that we can.

If you wish to contribute actively, you're very welcome to join the public-html-testsuite@w3.org mailing list (low traffic) by signing up to our mailing list.