Tests in python ports

Hi,

The upstream for devel/py-proxmoxer removed the tests/ directory from 
their sdist published on PyPI in 
https://github.com/proxmoxer/proxmoxer/pull/39

Now I've created an issue with upstream, but I'm getting some pushback, 
mostly asking why we don't fetch the source from github?

The python ports guidelines clearly state:
---
Guideline: Use standard Python ecosystem infrastructure whenever possible.

     Ports SHOULD use MASTER_SITES=CHEESESHOP if a Python package is 
registered on PyPI, unless there is a compelling (temporary) case not to.

Examples where temporarily using an alternate MASTER_SITES is warranted:

     Some files are not correctly packaged or included at all in the 
PyPI sdist, such as licenses, test suite files or data. Submit an 
upstream issue or PR in these cases.
     A source distribution (sdist) has not been uploaded yet
---

Is it common for python projects to not include tests in PyPI 
distribution? Is there a good argument I can point to, besides their use 
in ports, for including tests?

.einar