Re: RFC: adding pytest as a supported test framework

On Wed, 12 Jun 2024 at 17:50, Andres Freund <andres@anarazel.de> wrote:
> > The OAuth pytest suite makes extensive use of
> > - psycopg, to easily drive libpq;
>
> That's probably not going to fly. It introduces painful circular dependencies
> between building postgres (for libpq), building psycopg (requiring libpq) and
> testing postgres (requiring psycopg).
>
> You *can* solve such issues, but we've debated that in the past, and I doubt
> we'll find agreement on the awkwardness it introduces.

psycopg has a few implementations binary, c, & pure python. The pure
python one can be linked to a specific libpq.so file at runtime[1]. As
long as we don't break the libpq API (which we shouldn't), we can just
point it to the libpq compiled by meson/make. We wouldn't be able to
use the newest libpq features that way (because psycopg wouldn't know
about them), but that seems totally fine for most usages (i.e. sending
a query over a connection). If we really want to use those from the
python tests we could write our own tiny CFFI layer specifically for
those.

> One thing worth thinking about is that such dependencies have to work on a
> relatively large number of platforms / architectures. A lot of projects
> don't...

Do they really? A bunch of the Perl tests we just skip on windows or
uncommon platforms. I think we could do the same for these.