web-platform-tests quarterly update - Q4 2020

[Stephen Mcgruer]

[This update covers both work done by the Chromium Ecosystem Infra team and by members of the wider WPT community.]

Do you use - or want to use - WPT for your tests? Check out this brief taste of what has been happening in WPT over the last 3 months!

What's New?

WPT has officially switched to Python 3! After a year-long effort spearheaded by our friends at Igalia, and helped along the way by many folks from both Chromium and the WPT community, we finally flipped the switch and went Python3-first in WPT (corresponding Blink change). WPT will remain Python2-compatible until ~Feb 2021, at which point it will become Python3-only and we will get to delete a whole bunch of migration code - woo!

Support for testing WebSockets over HTTP/2. Thanks to a great contribution from @arenevier, it is now possible to test browser support for WebSockets over HTTP/2 in upstream WPT (rfc, implementation). Note that HTTP/2 is not yet supported in the Chromium CI (tracking bug).

WPT @ TPAC 2020. As usual, the WPT community met (virtually!) at this year's TPAC. Over two days of meetings we discussed topics ranging from test automation, to supporting the CSSWG, to surfacing high priority test failures. Check out this summary of the meetings, and our 2021 priorities document.

Tips & Tricks

An example test using test_driver.delete_all_cookies() to clear out a cookie set via document.cookie = "test1=1";

Want to be sure you have a fresh state for tests that use cookies? Thanks to Mike Taylor (miketaylr@), testdriver.js now has a delete_all_cookies method (documentation) that will clear all set cookies - even if they are HttpOnly!

Minor anti-aliasing or font artifacts causing you grief in a reftest? Fuzzy reftesting can help! This WPT feature allows you to define some 'fuzz' to a reftest comparison, so that minor differences are ignored (and it now works in blinkpy!). Check out the documentation.

Upcoming Work

As this is the final update of the year, I wanted to use this section to touch on where WPT might go in 2021. In many ways, the project has reached a point of maturity - being a core part of testing in Chromium and Gecko, and with WebKit ramping up their interest over the past year.

That said, there's still plenty of work to do! One core theme that came up at TPAC was continuing to make it possible/easier to use WPT for feature testing. This covers both continuing to invest in test automation (e.g. WebDriver BiDi, looking at a browser testing API spec) as well as improving test ergonomics (a long-standing pain point). The other strong theme was using data from WPT to push forward on browser interop - ideas here included surfacing more interop-focused data on wpt.fyi and continuing to support WebKit's integration with WPT.

I expect to see work on both these themes in 2021 for WPT but, as always, we'd love your input. You can reach us at ecosyst...@chromium.org any time.

Happy holidays all!

Thanks,

Stephen