A few days ago setuptools, a library used in many packages as an installer, released its version V72, removing support for calling setup.py test to run said package tests. The test command was proposed for deprecation in 2017, so 7 years ago, but the Python community is massive, cares about stability, and comes with a proportional inertia.
A few days ago a ticket has been opened to signal that many packages were not installable anymore after this change. If you wonder how a test command could break package installation, that's one of the numerous downsides of using an executable format such as setup.py: it executes code, things get imported, and if they are not there, it breaks.
That's why the current best practice is to use pyproject.toml for metadata, and the wheel format to package things. It's all declarative, so those problems are less likely to happen.
And if you are still using setuptools or setup.py as a lib publisher, consider migrating your package to more modern practices if your use case allows it, which is almost always the case.