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Latest commit 42bd902 Nov 20, 2017 @mikewest mikewest committed with chromium-wpt-export-bot Add custom element event tests for CSP nonce hiding.
Basically copy-pasting from Anne's suggestions at
whatwg/html#2373 (comment)

Bug: 680419
Change-Id: I9fee18d46dc00ff3ec8ec90f3d8acd80ab015622
Reviewed-by: Andy Paicu <>
Commit-Queue: Mike West <>
Cr-Commit-Position: refs/heads/master@{#517734}
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.well-known Add README in /.well-known/ to explain why mock-idp.js is hosted there Aug 8, 2017
2dcontext Remove executable bit from files that definitely aren't (#7756) Oct 13, 2017
FileAPI Remove zcorpan from OWNERS files Sep 11, 2017
IndexedDB IndexedDB: Enable WASM decoding in structured cloning done when writing. Nov 14, 2017
WebCryptoAPI Fix WebCryptoAPI tests (#8284) Nov 17, 2017
WebIDL Remove some odd old files (#7311) Sep 13, 2017
XMLHttpRequest Avoid decoding XHR type="json" responses as UTF-16BE/LE Nov 15, 2017
accelerometer Make concrete sensor IDL tests use standalone IDL files (#8004) Oct 31, 2017
acid Add a README to acid/ Oct 23, 2017
ambient-light Make concrete sensor IDL tests use standalone IDL files (#8004) Oct 31, 2017
annotation-model Annotation model fixreqs (#4232) Dec 13, 2016
annotation-protocol Remove executable bit from files that definitely aren't (#7756) Oct 13, 2017
annotation-vocab Annotation vocabulary setup (#4231) Nov 22, 2016
apng Add a web platform test for APNG Apr 12, 2017
audio-output Merge pull request #7010 from dontcallmedom/setsinkid Aug 28, 2017
background-fetch Align 'IsPotentiallyTrustworthy' with the spec for `localhost`. Oct 21, 2017
battery-status Battery Status: Add [Exposed=Window] to Web IDL test Oct 3, 2017
beacon Merge pull request #6655 from Brandr0id/sendBeaconTests Aug 15, 2017
bluetooth Add specific error for Bluetooth's test (#5516) Apr 10, 2017
clear-site-data Verify that various backends are deleted with the "storage" datatype Aug 4, 2017
clipboard-apis Move clipboard/OWNERS into clipboard-apis/ (#7268) Sep 7, 2017
common Get rid of /common/vendor-prefix.js Sep 29, 2017
compat Test that webkitHidden and webkitVisibilityState do not exist (#6983) Aug 25, 2017
conformance-checkers cc Reword “Element `foo` not allowed” messages Oct 4, 2017
console Add console timeline timelineEnd historical tests Mar 30, 2017
content-security-policy Add custom element event tests for CSP nonce hiding. Nov 19, 2017
cookie-store Update cookie-related OWNERS and READMEs Nov 16, 2017
cookies Update cookie-related OWNERS and READMEs Nov 16, 2017
core-aam Core-AAM: More fixes for IAccessible2 assertions (#7682) Oct 12, 2017
cors CORS: Access-Control-Expose-Headers and invalid values May 19, 2017
credential-management Initial upload to reland 578729. Aug 22, 2017
css-contain Style containment applies to display:content elements. Nov 16, 2017
css [PaintWorklet] Pass snapped concrete size to paint function Nov 15, 2017
custom-elements Editorial: Remove whitespace from custom-elements/OWNERS (#8158) Nov 12, 2017
docs Update introduction documentation. (#8183) Nov 15, 2017
dom Add a test for the removal of Event::getPreventDefault. (#8274) Nov 17, 2017
domparsing Update domparsing spec links to not point at WHATWG Oct 16, 2017
domxpath Make the XPath IDL tests tentative (#7639) Oct 9, 2017
dpub-aam WAI: Updated tests for wai-aria and dpub-aam (#5877) May 10, 2017
dpub-aria Dpub vocab (#4387) Jan 31, 2017
editing Add webplatform-test for testing "insertParagraph" command when user-… Nov 15, 2017
encoding TextCodecICU: respect encoder state when replacing unencodables Nov 10, 2017
encrypted-media Make getUserMedia throw DOMException or OverconstrainedError Nov 14, 2017
entries-api entries-api: Don't use const for loop variable Oct 11, 2017
eventsource Make EventTarget Constructible & Subclassable in JavaScript Nov 10, 2017
feature-policy Make getUserMedia throw DOMException or OverconstrainedError Nov 14, 2017
fetch Fetch: adjust Content-Length value in cors-filtering.js Nov 9, 2017
fonts Update Ahem to latest from AhemMaker Sep 21, 2017
fullscreen Don't SetContainsFullScreenElement() when inserting elements Nov 17, 2017
gamepad Update the getGamepads() IDL syntax to match the spec Nov 13, 2017
generic-sensor Fix racy issue and use onreading to monitor sensor reading (#8041) Nov 3, 2017
geolocation-API Cleanup testharness-related code (#5559) May 5, 2017
geolocation-sensor Test Geolocation Sensor IDL Nov 15, 2017
gyroscope Make concrete sensor IDL tests use standalone IDL files (#8004) Oct 31, 2017
hr-time Update IDL with HR time L2 Sep 26, 2017
html-imports Remove more testharness.css links (#2217) Mar 31, 2016
html-longdesc Add OWNERS files generated from commit log. Feb 2, 2016
html-media-capture HTML Media Capture: update Web IDL tests (#6272) Aug 15, 2017
html Fix lint errors introduced in #8261 Nov 16, 2017
http HTTP Refresh header Aug 9, 2017
imagebitmap-renderingcontext Clean up ImageBitmapRenderingContext tests Nov 14, 2016
images Added smiley.png.headers. Aug 31, 2017
infrastructure Link to from infrastructure/ Oct 8, 2017
innerText Test multiple text nodes with innerText Nov 8, 2017
input-events [InputEvent] Rewrite typing and getTargetRanges() tests into WPT Sep 15, 2017
interfaces Test Geolocation Sensor IDL Nov 15, 2017
intersection-observer style: Add some more tests for disallowed rootMargin values. Oct 30, 2017
js Use assert_in_array instead of assert_true(x === y || x === z) May 18, 2017
keyboard-lock Rename KeyLock to KeyboardLock and return enum from IPC May 4, 2017
longtask-timing Omit reporting tasks whose local root does not match monitor's local … Oct 17, 2017
magnetometer Make concrete sensor IDL tests use standalone IDL files (#8004) Oct 31, 2017
mathml Add @fred-wang as a MathML owner Aug 1, 2017
media-capabilities Replace vp9 with vp09... in MediaCapabilities LayoutTests Nov 17, 2017
media-source Check default media type support with MediaSource.isTypeSupported() Jul 12, 2017
media Moved webm files from mediacapture-fromelement/webm/ to media/ so the… Jul 28, 2017
mediacapture-fromelement [mediacapture-fromelement] Support Firefox moz-prefixed implementatio… Oct 4, 2017
mediacapture-image Image Capture: add idlharness WPT May 4, 2017
mediacapture-record MediaRecoder: add idlharness WPT Mar 19, 2017
mediacapture-streams Make getUserMedia throw DOMException or OverconstrainedError Nov 14, 2017
mediasession Media Session: move all tests but mojo/ ones to external/wpt/. Feb 9, 2017
mixed-content Rework mixed content tests. (#7938) Oct 25, 2017
navigation-timing Synchronize the WebILD definition Sep 25, 2017
netinfo NetInfo: web platform tests for the saveData attribute Nov 7, 2017
notifications Marking tests as HTTPS. Feb 27, 2017
offscreen-canvas Fix OffscreenCanvas resizing behavior Aug 22, 2017
old-tests/submission old-tests: remove webdriver tests Oct 16, 2017
orientation-event orientation-event: Update idlharness.js tests Mar 23, 2017
orientation-sensor Make concrete sensor IDL tests use standalone IDL files (#8004) Oct 31, 2017
page-visibility Merge branch 'pv_onvisibilitychange' into plh/page-visibility/onvisib… Jul 26, 2017
paint-timing Add paint-timing test when child iframe paints Nov 14, 2017
payment-handler Add initial payment handler tests. (#7037) Sep 7, 2017
payment-method-basic-card Remove @alphan102, add @mnoorenberghe Oct 10, 2017
payment-method-id chore(payment-method-id): create dir for incoming tests Jul 21, 2017
payment-request Remove redundant test (tested elsewhere) Nov 4, 2017
performance-timeline Merge pull request #7474 from w3c/perf-timeline/observe/typeerr Oct 2, 2017
pointerevents Intermittent pointerevent_touch-action-button-test_touch-manual.html.… Nov 15, 2017
pointerlock [PointerLock] Add null check before dispatching click event May 5, 2017
preload Link rel=modulepreload: Add comments that map code to the spec Nov 16, 2017
presentation-api [Media Router] Update Cast Presentation URL logic - tests only Sep 26, 2017
proximity followup. Fix web platform tests that either depended on the old spec… Jan 3, 2017
quirks-mode Remove zcorpan from OWNERS files Sep 11, 2017
referrer-policy Inherit referrer and policy when creating a nested browsing context Oct 24, 2017
remote-playback [RemotePlayback] Fix layout tests for remote playback. Jun 19, 2017
requestidlecallback Added an IdleDeadline object for the test (#7478) Oct 25, 2017
resize-observer Tests for ResizeObserver (#6878) Oct 2, 2017
resource-timing Resource Timing: Do not report subsequent navigations within subframes Nov 3, 2017
resources Add cache-control headers for testharness* files. (#8115) Nov 10, 2017
screen-orientation Add marcoscaceres as owner Feb 27, 2017
secure-contexts Restrict secure<=>non-secure SharedWorker creation. Nov 16, 2017
selection Move Microsoft's collapse.html to the test suite. Oct 4, 2017
server-timing Server Timing - duplicate names WPT Aug 25, 2017
service-workers P13 Add a WPT test that verifies data streams through respondWith(). Nov 15, 2017
shadow-dom Set relatedTarget to null if target is null in DispatchEventPostProcess Oct 18, 2017
speech-api Update OWNERS Oct 18, 2017
staticrange [InputEvent] Make StaticRange immutable and move tests to wpt Apr 14, 2017
storage Add real baselines for new .any.js and .worker.js tests (batch 1 of N) Jul 26, 2017
streams Add test for erroring teed ReadableStreams with canceled branches Nov 17, 2017
subresource-integrity Test Ed25519 signatures with CSP. Aug 25, 2017
svg-aam Placeholder for svg-aam tests Jan 31, 2017
svg Test SVG <use> element matching rules. Nov 15, 2017
tools Make error messages around /etc/hosts more consistent Nov 17, 2017
touch-events Expand on the Touch constructor tests (#3748) Sep 29, 2016
trusted-types Fix a no-op Trusted Types test. Oct 9, 2017
uievents Clean up click-cancel.html a bit Nov 7, 2017
upgrade-insecure-requests Basic tests for Upgrade-Insecure-Requests. (#4292) Dec 8, 2016
url Add test for fragment handling in data URIs (#8109) Nov 14, 2017
user-timing upadte pull request #4976 Jul 26, 2017
vibration Get rid of /common/vendor-prefix.js Sep 29, 2017
visual-viewport Fix visualViewport expectations at 2x browser-zoom. Nov 3, 2017
wai-aria wai-aria: Remove redundant AX API assertions from two aria-modal test… Oct 17, 2017
wake-lock Add feature policy for wake lock (#8022) Nov 13, 2017
wasm [wasm] IDB load/save across worker and main window Nov 7, 2017
web-animations Add test for AnimationPlaybackEvent constructor; Nov 15, 2017
web-nfc Web NFC: Convert Chromium Layout tests to testharness tests (#6490) Aug 2, 2017
web-share interfaces/web-share: Changed IDL to match spec change. Jul 7, 2017
webaudio Sync wpt/webaudio audit.js Nov 15, 2017
webauthn removing stray debug statement Oct 31, 2016
webdriver Test element retrieval from XHTML namespace. Nov 15, 2017
webgl Re-add webgl tests that aren't part of the upstream conformance suite. Nov 2, 2017
webmessaging Fix passing blobs on MessagePort and BroadcastChannel. Oct 23, 2017
webrtc Update OWNERS Nov 16, 2017
websockets WebSocket handshake has no referrer Nov 17, 2017
webstorage Storage.idl: Drop [NotEnumerable], remove anonymous getter/setter/del… Oct 2, 2017
webusb Use in WebUSB tests Nov 7, 2017
webvr Renamed VRLayer to VRLayerInit to match WebVR spec Sep 5, 2017
webvtt Added font properties tests for ::cue-region and ::cue-region() Oct 16, 2017
workers Added exception-handling to worker wpt tests. Oct 12, 2017
worklets Worklet: Add tests for CSP directives on addModule() Nov 15, 2017
x-frame-options Fix lint errors May 18, 2017
.codecov.yml Add codecov configutation. (#5623) Apr 24, 2017
.gitignore add webdriver tests for Get Status command Jul 27, 2017
.gitmodules Add widlproc submodule Apr 19, 2017
.travis.yml Tag master with the PR id that merged at that point. (#8005) Nov 7, 2017 Meta: make point to documentation Mar 16, 2017 Fix the first header in the license file (#5244) Mar 28, 2017 Add a note to recommend `git fetch -p` Nov 14, 2017
check_stability.ini change webhook URL and add functionality for each job to post to bot Aug 9, 2017
config.default.json Add pregenerated certificates to the repo and use them by default. Aug 21, 2017
lint.whitelist Fix lint errors introduced in #8261 Nov 16, 2017 Add a warning when running ./serve when tools.serve cannot be imported ( Oct 30, 2016 Make tests self-hosting Jan 6, 2014
testharness_runner.html Add testharness_runner file here for now. Apr 17, 2015 Make match assumptions move Oct 7, 2017
wpt Add a wpt command as a frontend to all cli interactions. Jul 26, 2017 Allow |python wpt <command>| to work on Windows. Aug 16, 2017

The web-platform-tests Project IRC chat

The web-platform-tests Project is a W3C-coordinated attempt to build a cross-browser testsuite 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.

Setting Up the Repo

Clone or otherwise get

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 following entries are required:   web-platform.test   www.web-platform.test   www1.web-platform.test   www2.web-platform.test   xn--n8j6ds53lwwkrqhv28a.web-platform.test   xn--lve-6lad.web-platform.test     nonexistent-origin.web-platform.test

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

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"]

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 preceed the prior command with python or the path to the python binary.

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 examaple 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 archive for your platform from [](Mozilla CI)

Then extract certutil[.exe] from the 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.


Some optional components of web-platform-tests (test components from third party software and pieces of the CSS build system) are included as submodules. To obtain these components run the following in the root of your checkout:

git submodule update --init --recursive

Prior to commit 39d07eb01fab607ab1ffd092051cded1bdd64d78 submodules were requried for basic functionality. If you are working with an older checkout, the above command is required in all cases.

When moving between a commit prior to 39d07eb and one after it git may complain

$ git checkout master
error: The following untracked working tree files would be overwritten by checkout:

followed by a long list of files. To avoid this error remove the resources and tools directories before switching branches:

$ rm -r resources/ tools/
$ git checkout master
Switched to branch 'master'
Your branch is up-to-date with 'origin/master'

When moving in the opposite direction, i.e. to a commit that does have submodules, you will need to git submodule update, as above. If git throws an error like:

fatal: No url found for submodule path 'resources/webidl2/test/widlproc' in .gitmodules
Failed to recurse into submodule path 'resources/webidl2'
fatal: No url found for submodule path 'tools/html5lib' in .gitmodules
Failed to recurse into submodule path 'resources'
Failed to recurse into submodule path 'tools'

then remove the tools and resources directories, as above.

Windows Notes

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

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.


By default pregenerated certificates for the web-platform.test domain are provided in the repository. If you wish to generate new certificates for any reason it's possible to use OpenSSL when starting the server, or starting a test run, by providing the --ssl-type=openssl argument to the wpt serve or wpt run commands.

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"}}

On Windows using OpenSSL typically requires installing an OpenSSL distribution. Shining Light provide a convenient installer that is known to work, but requires a little extra setup, i.e.:

Run the installer for Win32_OpenSSL_v1.1.0b (30MB). During installation, change the default location for where to Copy OpenSSL Dlls from the System directory to the /bin directory.

After installation, ensure that the path to OpenSSL (typically, this will be C:\OpenSSL-Win32\bin) is in your %Path% Environment Variable. If you forget to do this part, you will most likely see a 'File Not Found' error when you start wptserve.

Finally, set the path value in the server configuration file to the default OpenSSL configuration file location. 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 (typically this will be C:\\OpenSSL-Win32\\bin\\openssl.cfg).


The master branch is automatically synced to

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.

Finding Things

Each top-level directory matches the shortname used by a standard, with some exceptions. (Typically the shortname is from the standard's corresponding GitHub repository.)

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.


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.


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.

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.

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 tools subdir at the root of the repository, or

  • the tools subdir 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 mailing list (low traffic) by signing up to our mailing list. The mailing list is archived.

Join us on irc #testing (, port 6665). The channel is archived.