[Nix-dev] package test set up and tear down

[James Cook]

On 14 April 2015 at 05:54, Tomas Hlavaty
<tomas.hlavaty at knowledgetools.de> wrote:
> Hi all,
>
> I have a nix package expression with "doCheck = true;".  The tests
> require a RDBMS (postgresql for now).  preCheck creates postgresql roles
> and database and postCheck drops the roles and database.  However, if
> make check fails, postCheck is not executed and the database remains
> polluted (and needs manual intervention).  Is there a way to revert the
> changes made by preCheck reliably even if make check fails?  Something
> like postCheckFinally, maybe?
>
> What is the recommended way of testing such packages?  The only one I
> found was nixos/tests/trac.nix which somehow runs nixos specific tests
> and creates a VM for the database, which is then discarded somehow.  If
> this is the way to go, do you have some pointers or examples I could
> follow about how to create and run these tests?
>
> I also found
> https://nixos.org/wiki/Kiberpipa_sprint_2014_topics_wiki_backup#Nixtest_-_testing_for_nixpkgs
> so it seems that there is a demand better package testing.  Have there
> been any progress on this front?
>
> Thank you,
>
> Tomas

Touching a global DB from the build process sounds risky in terms of
reproducibility. E.g. building two versions at the same time might not
work. Ideally, some way of isolating the test (e.g. the VM method you
mentioned) sounds like the right path, though I'm afraid I have no
advice to offer there.

IMO disabling tests for the time being is preferrable to running tests
that touch global state.

James