The Web Platform Tests Project 
The Web Platform Tests Project is a W3C-coordinated attempt to build a cross-browser testsuite for the Web-platform stack. However, for mainly historic reasons, the CSS WG testsuite is in a separate repository, csswg-test. Writing tests in a way that allows them to be run in all browsers gives browser projects confidence that they are shipping software that is compatible with other implementations, and that later implementations will be compatible with their implementations. This in turn gives Web authors/developers confidence that they can actually rely on the Web platform to deliver on the promise of working across browsers and devices without needing extra layers of abstraction to paper over the gaps left by specification editors and implementors.
Running the Tests
The tests are designed to be run from your local computer. The test environment requires Python 2.7+ (but not Python 3.x). You will also need a copy of OpenSSL. Users on Windows should read the Windows Notes section below.
To get the tests running, you need to set up the test domains in your
hosts file. The
following entries are required:
127.0.0.1 web-platform.test
127.0.0.1 www.web-platform.test
127.0.0.1 www1.web-platform.test
127.0.0.1 www2.web-platform.test
127.0.0.1 xn--n8j6ds53lwwkrqhv28a.web-platform.test
127.0.0.1 xn--lve-6lad.web-platform.test
0.0.0.0 nonexistent-origin.web-platform.test
Because web-platform-tests uses git submodules, you must ensure that these are up to date. In the root of your checkout, run:
git submodule update --init --recursive
The test environment can then be started using
./serve
This will start HTTP servers on two ports and a websockets server on
one port. By default one web server starts on port 8000 and the other
ports are randomly-chosen free ports. Tests must be loaded from the
first HTTP server in the output. To change the ports, copy the
config.default.json file to config.json and edit the new file,
replacing the part that reads:
"http": [8000, "auto"]
to some port of your choice e.g.
"http": [1234, "auto"]
If you installed OpenSSL in such a way that running openssl at a
command line doesn't work, you also need to adjust the path to the
OpenSSL binary. This can be done by adding a section to config.json
like:
"ssl": {"openssl": {"binary": "/path/to/openssl"}}
Windows Notes
Running wptserve with SSL enabled on Windows typically requires installing an OpenSSL distribution. Shining Light provide a convenient installer that is known to work, but requires a little extra setup.
After installation ensure that the path to OpenSSL is on your %Path%
environment variable.
Then set the path to the default OpenSSL configuration file (usually
something like C:\OpenSSL-Win32\bin\openssl.cfg in the server
configuration. To do this copy config.default.json in the
web-platform-tests root to config.json. Then edit the JSON so that
the key ssl/openssl/base_conf_path has a value that is the path to
the OpenSSL config file.
Alternatively, you may also use Bash on Ubuntu on Windows in the Windows 10 Anniversary Update build, then access your windows partition from there to launch wptserve.
Test Runner
There is a test runner that is designed to provide a convenient way to run the web-platform tests in-browser. It will run testharness.js tests automatically but requires manual work for reftests and manual tests.
The runner can be found at /tools/runner/index.html on the local
server i.e.
http://web-platform.test:8000/tools/runner/index.html
in the default configuration. The first time you use this it has to generate a manifest of all tests. This may take some time, so please be patient.
Publication
The master branch is automatically synced to http://w3c-test.org/.
Pull requests that have been checked are automatically mirrored to http://w3c-test.org/submissions/.
Finding Things
Each top-level directory represents a W3C specification: the name matches the shortname used after the canonical address of the said specification under http://www.w3.org/TR/ .
For some of the specifications, the tree under the top-level directory 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 in HTML 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.
Branches
In the vast majority of cases the only upstream branch that you
should need to care about is master. If you see other branches in
the repository, you can generally safely ignore them.
Contributing
Save the Web, Write Some Tests!
Absolutely everyone is welcome (and even encouraged) to contribute to test development, so long as you fulfill the contribution requirements detailed in the Contributing Guidelines. 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).
- Create a branch for your changes:
git checkout -b topic. - Make your changes.
- Run the lint script described below.
- Commit locally and push that to your repo.
- Send in a pull request based on the above.
Lint tool
We have a lint tool for catching common mistakes in test files. You
can run it manually by starting the lint executable from the root of
your local web-platform-tests working directory like this:
./lint
The lint tool is also run automatically for every submitted pull request, and reviewers will not merge branches with tests that have lint errors, so you must fix any errors the lint tool reports. For details on doing that, see the lint-tool documentation.
But in the unusual case of error reports for things essential to a
certain test or that for other exceptional reasons shouldn't prevent
a merge of a test, update and commit the lint.whitelist file in the
web-platform-tests root directory to suppress the error reports. For
details on doing that, see the lint-tool documentation.
Adding command-line scripts ("tools" subdirs)
Sometimes you may want to add a script to the repository that's meant to be used from the command line, not from a browser (e.g., a script for generating test files). If you want to ensure (e.g., for security reasons) that such scripts won't be handled by the HTTP server, but will instead only be usable from the command line, then place them in either:
the
toolssubdir at the root of the repository, orthe
toolssubdir at the root of any top-level directory in the repository which contains the tests the script is meant to be used with
Any files in those tools directories won't be handled by the HTTP
server; instead the server will return a 404 if a user navigates to
the URL for a file within them.
If you want to add a script for use with a particular set of tests but
there isn't yet any tools subdir at the root of a top-level
directory in the repository containing those tests, you can create a
tools subdir at the root of that top-level directory and place your
scripts there.
For example, if you wanted to add a script for use with tests in the
notifications directory, create the notifications/tools subdir and
put your script there.
Test Review
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.
OWNERS files are used only to indicate who should be notified of pull requests. If you are interested in receiving notifications of proposed changes to tests in a given directory, feel free to add yourself to the OWNERS file. Anyone with expertise in the specification under test can approve a pull request. In particular, if a test change has already been adequately reviewed "upstream" in another repository, it can be pushed here without any further review by supplying a link to the upstream review.
Getting Involved
If you wish to contribute actively, you're very welcome to join the [email protected] mailing list (low traffic) by signing up to our mailing list. The mailing list is archived.
Join us on irc #testing (irc.w3.org, port 6665). The channel is archived.