As mentioned in the chapter on Testing, we run the full Puppeteer test suite on try. These tests are vendored in central under remote/test/puppeteer/ and we have a script to pull in the most recent changes.
We currently use [a fork of Puppeteer] with a small number of tweaks and workaround to make them run against Firefox. These changes will be upstreamed to Puppeteer when we feel more comfortable about compatibility with Chrome.
To update the vendored copy of Puppeteer under remote/test/puppeteer/:
% ./mach remote vendor-puppeteer
This will replace the current checkout with a fresh copy from
the predefined remote, which currently is the
firefox branch on
https://github.com/andreastt/puppeteer.git. You can override which
remote and commit to use.