Execute CI tests in Cygwin (should we?)

[Vitaly Potyarkin]

I've recently learned that pexpect works correctly under Cygwin (if Python is also installed via Cygwin).

At first glance that seems to be a reasonable way to execute CI tests on Windows, but does that really add any extra value? Cygwin environment is much more similar to traditional Unices than to the OS it's running on. On the other hand, bash itself is not really a native Windows app - it requires either WSL or msys or Cygwin to work...

I'm leaving this here to gather some feedback.

Some relevant links that may be helpful if we decide to go this route:

• https://cygwin.com/faq/faq.html#faq.setup.cli
• https://gist.github.com/wjrogers/1016065/385cfab346638f9d99b15e93eeda61ff1ae0a6c5
• https://potyarkin.com/posts/2020/cygwin-ci-journey/

[Vitaly Potyarkin]

I have recently learned that GitHub Actions environment for windows-latest provides msys2 outside of PATH. I implemented a CI job on top of that.

Msys2 is a weird cross-breed of Cygwin and native apps, but for our purposes I think it's close enough. I will close this issue now but if anyone thinks that pure Cygwin would be beneficial - do not hesitate to make a PR.