Add support for loading Products.* packages outside the Products install folder

[gforcada]

See plone/Products.CMFDynamicViewFTI@2531d00 for the actual code (from plone/Products.CMFDynamicViewFTI#24)

Rationale:

If you are running tests from within a Products.* distribution you will probably have all other Products installed somewhere in lib/python3.11/site-packages/... but the distribution under test will be used from its source files.

Turns out that plone.testing specifically looks for Products.* distributions to be always from the very same location, ignoring distributions that are used outside the Products folder within site-packages.

Do we still need this specific check, or is a relic of the past? 🤔

[davisagli]

@gforcada Where is the check? It might have something to do with namespace packages (or handling Products from before it was commonly understood how to use namespace packages) but I am not sure. I was going to take a closer look but I didn't find it yet.

[gforcada]

It's on Zope code, now i'm on the phone, I will check later

[gforcada]

Found it: https://github.com/plone/plone.testing/blob/master/src/plone/testing/zope.py#L47

This get_product checks the filesystem location of Products folder

[Rudd-O]

I support this effort.