Test suite: take into account that click-to-play is not required anymore for WebM videos in Tor Browser

Originally created by @intrigeri on #14586 (Redmine)

The “Watching a WebM video” test suite scenario now fails because it expects a click-to-play icon, and instead the video is played directly.

I can reproduce this on Tails 3.1, but not on 3.0 nor 3.0.1. This should have been noticed & reported when running the automated test suite during the 3.1 release, instead of 3.5 weeks later by pure luck. bertagaz, did you report this in another ticket that I’ve missed? If not, please ensure the release process doc makes it clear that such things need to be reported during the testing session.

I guess this change was brought by Tor Browser 7.0.4. The only related item in its changelog is https://trac.torproject.org/projects/tor/ticket/22067, which is supposed to make click-to-play stronger in some cases, rather than to skip it entirely in some (other?) cases.

Regardless, according to https://www.torproject.org/projects/torbrowser/design/#other-security, click-to-play is only enabled when the security slider is set to Medium or higher, so this new behaviour seems to be a feature rather than a bug => treating this as a test suite maintenance task. It’s not super high priority so this can wait until 3.3 IMO.

Feature Branch: test/14586-browser-webm-without-click-to-play

Related issues

• Blocks #13239 (closed)