> 3. use a separate virtualenv when running under `make test`,
without
> --system-site-packages if possible, and ensure up-to-date deps are always
> installed, to eliminate any differences that can occur on different setups
> The only problem I see here, is that some of the packages that
you'd need
> to
> install into the test-virtualenv need some C-compilation when installing
> from PyPi, and that (if used without the --system-site-packages) would mean
> having to install not only gcc but also plenty of -dev packages.
> Not a _huge_ ussue but an issue nevertheless.
That's a good point. But do we have a good alternative here? If
we depend on
packages like that, I see only two options:
a) ask the person to install pyfoo as an RPM (in readme)
b) ask the person to install gcc and libfoo-devel as an RPM (in readme) and
pyfoo will be then compiled and installed from pypi
Approach a) is somewhat easier and does not require compilation stack
and
devel libraries. OTOH it requires using virtualenv with
--system-site-packages, which means people get different results on
different setups. That's exactly what I'm trying to eliminate (or at least
reduce). E.g.
https://phab.qa.fedoraproject.org/D1111 where I can run the
test suite from makefile and you can't, and it's quite difficult to figure
out why.
With b) approach, you need compilation stack on the system. I
don't think
it's such a huge problem, because you're a developer after all. The
advantage is that virtualenv can be created without --system-site-packages,
which means locally installed libraries do not affect the execution/test
suite results. Also, pyfoo is installed with exactly the right version,
further reducing differences between setups. The only thing that can differ
is the version of libfoo-devel, which can affect the behavior. But the
likeliness of that happening is much smaller than having pyfoo of a
different version or pulling any deps from the system site packages.
Sigh, OTOH Josef has a very good point in
https://phab.qa.fedoraproject.org/D1112#20744
that figuring out which devel packages are needed on the system for pypi module
compilation is quite a non-trivial task. Seems harder than figuring out which packages you
need to install on the system when using --system-site-packages.
So, I don't really see a simple solution here that would guard us from inconsistent
dev setups (system site packages) or not require us to have a painful deps maintenance (no
system site packages, but devel packages) :/
Even if we decide to keep --system-site-packages for simplicity, I can implement all the
rest of the proposed improvements. Just the reliability will not be as great as I wished.
The main question is now, I believe, whether we want to install compilation-dependent
packages from pypi or rpm.