> On GitHub Actions, we’re planning to use uv to quickly build a Python environment and run our unit tests. In production, uv already manages Python for all of our servers.
Does that mean they aren't running unit tests _at all_ in CI yet, or they just use a totally different, newer system in production than they do for CI? Either way, brave of them to admit that in public.
My team just did this.
It wasn't anything like the radical change to how CI works that you seem to be envisioning. It was just deleting a lot of Python environment setup and management code that has a history of being obnoxious to maintain, and replacing it with a one-liner that, at least thus far, has given us zero fuss.
You updated _production_ before _testing_? Sorry but that just sounds like asking for a disaster.
It seems like you're reading things that people aren't writing.
I don't know how the author's company manages their stack, so I can't speak to how they do their testing. But I do know that in many companies run-time environment management in production is not owned by engineering and it's common for ops and developers to use different methods to install run-time dependencies in the CI environment and in the production environment. In companies that work that way, testing changes to the production runtime environment isn't done in CI; it's done in staging.
If that's at all representative of how they work, then "we didn't test this with the automated tests that Engineering owns as part of their build" does not in any way imply, "we didn't test this at all."
Tangentially, the place I worked that maintained the highest quality and availability standards (by far) did something like this, and it was a deliberate reliability engineering choice. They wanted a separate testing phase and runtime environment management policy that developers couldn't unilaterally control as part of a defense in depth strategy. Jamming everything into a vertically integrated, heavily automated CI/CD pipeline is also a valid choice, but one that has its roots in Silicon Valley culture, and therefore reaches different solutions to the same problems compared to what you might see in older industries and companies.