[webkit-dev] Another WPT bite

Mike Pennisi mike at bocoup.com
Tue May 9 12:56:51 PDT 2017

> One question I have is whether web platform tests can run under a regular
> HTTP server (maybe with appropriate configuration) or do we need something
> special? Is the WPT server more than just a web server with specific
> configuration settings?

While many tests can probably be run in this way, many others are dependent
on the functionality of the Web Platform Test Server. It's written in Python
and supports (among other things) arbitrary HTTP request handling via
standalone Python scripts. Its capabilities are documented here:


Like with `testharness.js`, this additional infrastructure is a case of
"simplicity versus power."

> Another consideration here is "would my test be useful for other browser
> vendors". I don't think the answer is a unanimous "yes", so I think we
> should only use WPT for tests that will think are worth sharing.

This is a good point. I'm currently migrating service worker tests from
Chromium to WPT, and I'm frequently coming across tests (or sometimes
specific assertions) that aren't appropriate for WPT.

> I'm also concerned that with 4 vendors upstreaming their WPT tests, the
> WPT repo will just become a morass of partially overlapping tests that
> takes 4x longer to run than a curated repo.

This gets at another consideration that hasn't been mentioned yet:
participating in WPT like this expands the responsibilities of authors and
reviewers.  Contributors may have to spend extra time cataloging their new
tests (or finding the correct test to extend). Likewise, reviewers will need
to develop some familiarity with certain sub-directories of WPT.

This can be kind of a drag, but only if you aren't committed to the
long-term benefits of sharing tests. From that perspective, meaningful
organization is just another part of the job, and the value accrues with
every new test.

Which is all to say: buy-in is important. If the team decides to participate in
WPT, folks ought to be excited about it!

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