A lot of Python packages assume that their tests will be run after installing the package. This is quite a reasonable assumption if you take that the tests are primarily run in dedicated testing environments such as CI deployments or test runners such as tox. However, this does not necessarily fit the Gentoo packaging model where packages are installed system-wide, and the tests are run between compile and install phases.
In great many cases, things work out of the box (because the modules are found relatively to the current directory), or require only minimal PYTHONPATH adjustments. In others, we found it necessary to put a varying amount of effort to create a local installation of the package that is suitable for testing.
In this post, I would like to shortly explore the various solutions to the problem we’ve used over the years, from simple uses of build directory to the newest ideas based on virtual environments.
Continue reading “From build-dir to venv — testing Python packages in Gentoo”
I’m a Gentoo developer for over 10 years already. I’ve been doing a lot of different things throughout that period. However, Python was pretty much always somewhere within my area of interest. I don’t really recall how it all started. Maybe it had something to do with Portage being written in Python. Maybe it was the natural next step after programming in Perl.
I feel like the upcoming switch to Python 3.9 is the last step in the prolonged effort of catching up with Python. Over the last years, we’ve been working real hard to move Python support forward, to bump neglected packages, to enable testing where tests are available, to test packages on new targets and unmask new targets as soon as possible. We have improved the processes a lot. Back when we were switching to Python 3.4, it took almost a year from the first false start attempt to the actual change. We started using Python 3.5 by default after upstream dropped bugfix support for it. In a month from now, we are going to start using Python 3.9 even before 3.10 final is released.
I think this is a great opportunity to look back and see what changed in the Gentoo Python ecosystem, in the last 10 years.
Continue reading “10 Years’ Perspective on Python in Gentoo”