The web-platform-tests Project

The web-platform-tests Project is a W3C-coordinated attempt to build a
cross-browser test suite for the Web-platform stack. 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.

The most important sources of information and activity are:

github.com/web-platform-tests/wpt:
the canonical location of the project's source code revision history and the
discussion forum for changes to the code
web-platform-tests.org: the documentation
website; details how to set up the project, how to write tests, how to give
and receive peer review, how to serve as an administrator, and more
web-platform-tests.live: a public
deployment of the test suite, allowing anyone to run the tests by visiting
from an Internet-enabled browser of their choice
wpt.fyi: an archive of test results collected from an
array of web browsers on a regular basis
Real-time chat room: the
IRC chat room named #testing on
irc.w3.org; includes participants located
around the world, but busiest during the European working day; all
discussion is archived here
Mailing list: a
public and low-traffic discussion list

If you'd like clarification about anything, don't hesitate to ask in the
chat room or on the mailing list.

Setting Up the Repo

Clone or otherwise get https://github.com/web-platform-tests/wpt.

Note: because of the frequent creation and deletion of branches in this
repo, it is recommended to "prune" stale branches when fetching updates,
i.e. use git pull --prune (or git fetch -p && git merge).

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).

On Windows, be sure to add the Python directory (c:\python2x, by default) to
your %Path% Environment Variable,
and read the Windows Notes section below.

To get the tests running, you need to set up the test domains in your
hosts file.

The necessary content can be generated with ./wpt make-hosts-file; on
Windows, you will need to precede the prior command with python or
the path to the Python binary (python wpt make-hosts-file).

For example, on most UNIX-like systems, you can setup the hosts file with:

./wpt make-hosts-file | sudo tee -a /etc/hosts

And on Windows (this must be run in a PowerShell session with Administrator privileges):

python wpt make-hosts-file | Out-File $env:systemroot\System32\drivers\etc\hosts -Encoding ascii -Append

If you are behind a proxy, you also need to make sure the domains above are
excluded from your proxy lookups.

Running Tests Manually

The test server can be started using

./wpt serve

On Windows: You will need to precede the prior command with
python or the path to the python binary.

python wpt serve

This will start HTTP servers on two ports and a websockets server on
one port. By default the web servers start on ports 8000 and 8443 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,
create a config.json file in the wpt root directory, and add
port definitions of your choice e.g.:

{
  "ports": {
    "http": [1234, "auto"],
    "https":[5678]
  }
}

After your hosts file is configured, the servers will be locally accessible at:

http://web-platform.test:8000/

https://web-platform.test:8443/ *

To use the web-based runner point your browser to:

http://web-platform.test:8000/tools/runner/index.html

https://web-platform.test:8443/tools/runner/index.html *

*See Trusting Root CA

Running Tests Automatically

Tests can be run automatically in a browser using the run command of
the wpt script in the root of the checkout. This requires the hosts
file setup documented above, but you must not have the
test server already running when calling wpt run. The basic command
line syntax is:

./wpt run product [tests]

On Windows: You will need to precede the prior command with
python or the path to the python binary.

python wpt run product [tests]

where product is currently firefox or chrome and [tests] is a
list of paths to tests. This will attempt to automatically locate a
browser instance and install required dependencies. The command is
very configurable; for example to specify a particular binary use
wpt run --binary=path product. The full range of options can be see
with wpt run --help and wpt run --wptrunner-help.

Not all dependencies can be automatically installed; in particular the
certutil tool required to run https tests with Firefox must be
installed using a system package manager or similar.

On Debian/Ubuntu certutil may be installed using:

sudo apt install libnss3-tools

And on macOS with homebrew using:

brew install nss

On other platforms, download the firefox archive and common.tests.tar.gz
archive for your platform from
Mozilla CI.

Then extract certutil[.exe] from the tests.tar.gz package and
libnss3[.so|.dll|.dynlib] and put the former on your path and the latter on
your library path.

Command Line Tools

The wpt command provides a frontend to a variety of tools for
working with and running web-platform-tests. Some of the most useful
commands are:

wpt serve - For starting the wpt http server
wpt run - For running tests in a browser
wpt lint - For running the lint against all tests
wpt manifest - For updating or generating a MANIFEST.json test manifest
wpt install - For installing the latest release of a browser or
webdriver server on the local machine.

Windows Notes

On Windows wpt commands must be prefixed with python or the path
to the python binary (if python is not in your %PATH%).

python wpt [command]

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 wpt commands.

Please make sure git and your text editor do not automatically convert
line endings, as it will cause lint errors. For git, please set
git config core.autocrlf false in your working tree.

Publication

The master branch is automatically synced to http://w3c-test.org/.

Pull requests are
automatically mirrored except those
that modify sensitive resources (such as .py). The latter require
someone with merge access to comment with "LGTM" or "w3c-test:mirror" to
indicate the pull request has been checked.

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][contributing]. 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.

Issues with web-platform-tests

If you spot an issue with a test and are not comfortable providing a
pull request per above to fix it, please
file a new issue.
Thank you!

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:

./wpt 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.

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 more details, see the lint-tool documentation.

jakebolam/wpt