I still see the warning in the output (for example here).

I think tracking all of them down is likely to be difficult, what's probably happening is some test not interested in timers causes some to be created, then cleared later when some other unrelated test has set up fake timers. I don't want to add the flag everywhere because the warning can actually be useful when running tests in isolation, and it seems unfair to force good tests to suppress it to accommodate bad tests.

Yeah I wasn't attempting to fix them all in one shot; do you think we should suppress the warning? It's definitely making the output a bit annoying. Or we could force it to be set in tsst_deps. These tests in particular seem to not be clearing their timers in their after() and my understanding is this option just makes it so that happens without the explicit clear later?