this fixes python-objgraph on the "python-team" branch

python-objgraph is a dependency of python-greenlet and python-greenlet 
is a dependency of a project I'm working on at my dayjob

the tests need to write some cache files otherwise they will fail

And they can't write if a HOME env variable is not set

I can't see why with python 3.10 this wasn't a problem but with python 
3.11 is

The commit message isn't ok, probably

And the formatting is not ok, probably

That's because I haven't been doing this for quite some time now and my 
setup and habits are a bit shacky

Please bear with me