On Wednesday I noticed that WebDriver tests always default to HTTP when loading test pages. Discussing that on Element (#Fission channel) kmag pointed out that the same currently happens for the Mochitest framework.

Given that the web is becoming HTTPS by default it would be very good to change the Mochitest behavior and get pages loaded via HTTPS by default instead.

I'm not sure how much work that would be, especially with possible test regressions in mind, but I feel this change should be done.

Tests that explicitly require HTTP would then have to opt-out.

Asking Andrew as owner of Mochitest what he thinks.

To give us a sense of the scope we are talking about, here's a quick try push with a sampling of mochitest tasks and https default scheme:

https://treeherder.mozilla.org/jobs?repo=try&revision=ba03e162b7d7060f5de7b833e915da5938964e00

(There are a number of failing tests, but many pass.)

Seems reasonable to me, I can't think of any reason not to switch. The failures can continue to run with http. I don't think we'll have bandwidth to push on this anytime soon though.

So the upcoming https-first work would actually help us here, which actually requires tests to use HTTPS. Right now I'm aware of bug 1732865 for devtools related mochitests. Maybe there are others or another meta bug that we could mark dependent on?

(In reply to Henrik Skupin (:whimboo) [⌚️UTC+1] from comment #3)

So the upcoming https-first work would actually help us here, which actually requires tests to use HTTPS. Right now I'm aware of bug 1732865 for devtools related mochitests. Maybe there are others or another meta bug that we could mark dependent on?

Hey Henrik, we are trying to enable https-first in Nightly soon (see Bug 1719271) and we are currently updating failing tests on treeherder so we can eventually enable it in Nightly. We make all bugs for updating tests block the Meta Bug 1704453 of https-first. I have not filed any other bugs or meta bugs.

FWIW, generally I am totally with you, since the web is migrating toward https, we should also migrate/update and use https for the majority of our testing going forward - thanks!

Sounds good. So (nearly) all existing mochitests will make use of HTTPS when accessing test files then. Lets mark bug 1704453 as dependency.