Today, i downloaded Python 3.9.2 from python.org (MD5 sum and signature verified), then i read README.srt file, saw the instructions asking to do 4 commands:

'make test' for Python takes how many hours to finish?? Mine is running for more than 8h!

'make' did not take long to finish. But 'make test' started at 11:02:29, now is 19:29:13, and the command is still running! More than 8h and 20 minutes long! The computer has a 2700.000 MHz processor, with 4 cores. In the first hours, all the CPUs were being used close to 100%. But now, they are fairly stable around 50% (all the 4, as i checked in the system monitor a few times).

Is this the normal time for Python testing itself?

Just wondering...
In the web instructions there is a warning.
In the README.rst there is a section below Testing called "Installing Multiple Versions" which is mostly regarding installing multiple versions from source. But between the two, I'm guessing there may be a problem with "default python version", which could have been another version preinstalled beforehand.

EDIT: python3 is linked to which python-3*?

Why not just install it using your distros package manager?

Even Debian has 3.9.2.
apt policy python3
python3:
Installed: 3.9.2-2
Candidate: 3.9.2-2

Anyway, most people who build software from source don't do the tests. Even a lot of Linux From Scratch builders don't do them except for really essential bits like glibc and gcc.

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Because i am not always using the latest version of Debian. I keep the distribution for some time. And there is a project i was installing which demands python version to be 3.9.2 or later (!).

Why Python 3.9.2 does not appear in

https://packages.debian.org/search?keywords=Python

?

Because you searched for Python, not Python3

1 members found this post helpful.

Really "intuitive"... not. >:-(

Anyway, i have Debian Stretch, which is old stable, right now. I plan to keep it until it passes the "old old stable" phase. It does not have a Python 3.9.2 package. Is it an argument to open a bug in the project that wants only python from and above this version?

Because you searched instead of checking the version
And of course it is not a bug.
Packages are written with specific dependencies because that is what the developer wants / needs for that package to work now and in the near future. The developer cannot know what distro & version you are using nor can he know what versions of the different apps you might have installed; he can only know what is required for his package to work.

It is up to you to make certain your machine meets the requirements if you want to use that particular package. I would guess from your description that it is possible that you only have python2 installed. If so then install python3 and you might have what is needed. Python2 & python3 can live together as you see above.