[dev] Fix py3-compatibility branch test
As discussed here here's the changes needed to fix the failing test in the py3-compatibility branch.
To fix the test, I made sure that when using issubclass
, we use a class instead of a class instance as that distinction matter in python-3.
I've also took the liberty of restoring the original test that used isinstance
.
This way we check the resolver interface with both issubclass
and isinstance
.