[bug#49981] wip: Introduce unit-tests.

[Christopher Baines <mail@cbaines.net>]

Mathieu Othacehe <othacehe@gnu.org> writes:

> I would like to convert the Guix tests in the "tests/" directory to
> derivations, in the exact same way as for the system tests in the
> "gnu/tests/" directory.
>
> For that, I propose to introduce a new <unit-test> record. This would
> allow us to select all the unit tests using the "all-unit-tests"
> procedure, and add them to the (gnu ci) module.
>
> This way, we could have a Cuirass specification for the unit tests, as
> we already have for the system tests, to spot regressions early on.
>
> Here's a patch that translates the "account.scm" test module to the new
> proposed mechanism. If there are no objections, I plan to convert all
> the remaining tests.

Running the tests in an automated manor would be good, but I am
concerned about the ramifications of converting them to be defined like
the system tests.

I think it's already possible to effectively run the tests for an
arbitrary commit by building (current-guix) or similar. That runs all
the tests, maybe a similar approach could be found that runs individual
tests or runs them in groups.

Converting the tests themselves in to things that have to be put in the
store to be run could make local development harder, and is a step
towards making guix harder to package and distribute. As an example, it
would probably be possible for the Debian package to continue running
the tests, but I'd expect that having to run a guix-daemon just to be
able to setup for the tests will make running them more difficult.

Chris