Slow PR test times

[kyay10]

I think we could consolidate some of the test runs because they have tasks in common. For instance, merging all the iOS and macOS tests into a singular workflow would likely do wonders. Maybe the same for Jvm + Android.

[nomisRev]

@kyay10

For instance, merging all the iOS and macOS tests into a singular workflow would likely do wonders.

So compile everything, run tests in parallel? 🤔 You think that will be faster in a single runner compared to many runners, or did I understand you incorrectly?

Feel free to experiment in a PR. It would be awesome to speed up the build 👍

[serras]

Note that in the past we've had to split the iOS + macOS + watchOS + tvOS tests into two groups, because running all of them in the same workflow took too much time. Those seem to be inherently slow, so we could potentially think of running only iOS and macOS only.

The other relatively simple way I could see of improving PR times is better caching of the Native artifacts (the /home/runner/.konan directory). Those need to be re-downloaded and extracted every time.

[serras]

For the record, right now the main offender is the Mac runner, which always takes around 30 minutes. GitHub provides a large runner for Mac, but it’s not free :(