#11702 move some signal code

[exarkun]

Scope and purpose

Fixes #11702

This was glyph's idea while looking at #11685 which refactored a lot of code but left all of the signal-handling pieces inside base.py and posixbase.py. I pulled this code movement out because the branch for #11685 is over 1000 lines of diff including these changes.

This is intended to be even less than a refactoring. It's just mechanical movement of source code from one place to another.

Diff coverage here is not great but all of the uncovered code was also uncovered in its original location and all this does is move it.

[twm]

The code movement and minor changes look reasonable to me. Definitely organizational improvement. Thanks for splitting this out!

From the coverage results I guess we aren't running any CFReactor tests in CI? That seems bad, but oh well, Apple makes it such a pain to their users' detriment.

[adiroiban]

on macOS we only run 3.10-macos-12-default-tests , with the default reactor on macOS. I don't know which reactor is the default on macOS... I guess is the posix select.

I guess this is ok for now. If somebody cares about macOS, the CI infrastructure is ready to run the tests with a non-default reactor.
We do it for Windows, for which the tests are executed on both select and iocp.

Thanks Jean-Paul for the cleanup. Thanks Tom for the review.

[exarkun]

On the GitHub Actions macOS job, the CFReactor tests are all skipped like:

No module named 'CFNetwork'

So maybe it's just a matter of missing some dependencies.

[adiroiban]

So maybe it's just a matter of missing some dependencies.

Thanks. True. Those are the cfreactor targeted tests... and that would be a first step.

At least for windows, we also try to run the whole tests, not only the iocp tests, using the iocp reactor. For a better coverage, and in the case in which the targeted iocp have missing coverage.

[exarkun]

I filed #11708