Re: Exeter testing, next steps

[Stefano Brivio <sbrivio@redhat.com>]

On Tue, 5 Aug 2025 16:09:34 +1000
David Gibson <david@gibson.dropbear.id.au> wrote:

> Today I finally had a good look at what the next steps need to be if
> we are to use exeter based test "for real" in the passt repo.

\o/

> I already have draft series which move a bunch of the simpler tests to
> exeter.  But in order to actually use these we need some sort of
> runner.  We're not tied to that runner, we can easily change - that's
> the whole point of exeter - but we need to have something.

I guess as an even earlier first step we could actually have a
hardcoded shell script similar to today's test/run... or am I
misrepresenting the problem?

> AIUI, Stefano is not happy with the idea of using either Avocado or
> Meson as the default which were the runners I initially focused on for
> exeter.

I'm concerned about compatibility.

I don't actually see a problem with Meson *as a test runner* as it's
widely packaged, but as a build system, it's arguably less compatible
and more complicated than Make is (and we don't need all those features
to build passt).

> I now suggest two more options:
> 
> 1) Add a tool as part of exeter that will generate a BATS test script
>    from an exeter test program.  So you'd do something like:
> 
> 	$ exetool --bats <exeter_test_program> > foo.bats
> 	$ bats foo.bats
> 
> This should be pretty easy to do, it's basically what I already have
> for Avocado support, indeed a little easier.  For reasons internal to
> exeter, Python is the obvious choice to implement exetool, but I could
> do it in shell if you really don't like that.

As long as it can reasonably run on all the distributions where we
might want to run tests, I don't see an issue with Python. It depends a
bit on what the required modules are, I would say.

> 2) Hand-roll a minimal exeter runner as part of passt's existing test
>    scripts.  I'm thinking you could essentially point our test stuff
>    at an exeter program as an alternative to pointing it at a file
>    with the existing test DSL.
> 
>    This is more work, but still not too bad.  It has the advantage of
>    not adding another dependency, and means we could count exeter
>    results along with our existing test results in the final summary.

It also has the advantage of being conceptually simpler in that it
avoids one additional step and one additional "language" (Bats).

>    However, we'd lose parallel execution and filtering.

Aren't those sort of trivial once you have a "real" programming
language?

> Stefano, would you be willing to merge patches which add some basic
> exeter tests using one of these approaches?  This would probably just
> be static checked and build tests at this point, as a
> proof-of-concept.

Sure! As long as current tests keep working, of course.

> If we can start introducing some exeter tests, the next step would be
> to work on the support library stuff for constructing more complex
> network environments from namespaces.  I have draft series with this
> as well, but I was looking at splitting it into another mini-project
> (tentative name "sinte" - Simulated Inter Network Test Environment).

Neat! That sounds like the juicy part and surely one part we really
miss at this point. I would go as far as proposing PESTO (playground
environment simplifies test orchestration / spurs test opportunities)
but "sinte" sounds good to me as well.

-- 
Stefano