Hello,
I assume this topic is not specific to one package but to the whole
python packaging universe.
There is "backintime" which unittests do write to $HOME. I'm one of the
new upstream maintainers and know that this isn't a good idea. It will
take time to fix this.
About that problem there is a debian bug report nearly 4 years old
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=940319
It tells that this is a problem because writing to HOME during build "is
disabled on Debian auto-builders".
My question now is why newer version of this package are uploaded then?
I couldn't find that the tests where deactivated. Maybe this "disabled
on Debian auto-builders" is outdated and today it is possible to write
to HOME during build?