gh-129363: Added colored printing for python -m test without the -j flag

[lczyk]

Fixes #129363. New version based on RunWorkers::display_result.

• Issue: python -m test color print with and without -j #129363

[bedevere-app]

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[hugovk]

Thanks for this!

This isn't technically a bug, but does look like an improvement.

Now

Currently, yellow is shown for for skips, red for fail, and green when the time is shown:

What's going on is, the name is shown when it begins, and if it takes longer than 30 seconds to run, only then do we print an explicit result (with colour).

Those uncoloured lines are only stating the test started, and we don't show the result.

PR

The PR doesn't only add colour but changes functionality as well. Now it shows the result after it's finished running, and we don't get the uncoloured "start" line:

I think this an improvement? It makes it clear the test actually passed.

Comparison

Plus before, we'd get uncoloured .test_processes to show it's started, then when it completes, it prints uncoloured .test_threads to show the next test has started, but then a green .test_processes on the same line to show it's actually finished.

This is a little unclear to have the slow completion report show up after the bit about the next test starting:

However, with this PR, we only get the success lines:

cc @vstinner as well.

[hugovk]

Why check PGO? I don't think this was relevant before?

[vstinner]

I dislike the new behavior. It doesn't show the name of the test currently running. If a test takes 1 minute, for 1 minute, it says nothing. I prefer to know what's going on, which test is running.

I would prefer:

[  1/484] test.test_asyncio.test_base_events
[  1/484] test.test_asyncio.test_base_events passed
[  2/484] test.test_asyncio.test_buffered_proto
[  2/484] test.test_asyncio.test_buffered_proto passed
...

where the second line "passed" is green.

It's more verbose, but it's more explicit what's going on. Especially when a test is stuck.

[vstinner]

I would prefer: (...)

I wrote PR gh-129476 which does what I want :-) Please have a look.

[vstinner]

#129476 was merged instead. Thanks for your contribution anyway @MarcinKonowalczyk!

[lczyk]

yup, sorry, fell out the loop on this one. in favour of #129476 ! :))