Feature: pytest fixture for checking if signal was emmited

[Czaki]

It will be nice to have pytest fixture to check if the Signal was emitted. Something similar to qtbot.wati_singal and qtbot.wait_signals This will be really helpful when using tread propagation of Signals.

[tlambert03]

Totally agree.
Just a note though, you actually can use qtbot wait signals here!
There's even a test to make sure it works: https://github.com/tlambert03/psygnal/blob/main/tests/test_qtbot.py

Of course, that requires actually having a qt backend, which may in some cases defeat the purpose of this Lib, so it's still a good feature request.