[Qgis-psc] Handling the Travis CI situation

[Alessandro Pasotti]

On Mon, Nov 9, 2020 at 12:55 AM Nyall Dawson <nyall.dawson at gmail.com> wrote:
>
> On Fri, 6 Nov 2020 at 20:57, Matthias Kuhn <matthias at opengis.ch> wrote:
> >
> > This would be desirable.
> >
> > It's unfortunately a bit of complexity included. As Alessandro said, the rendering tests are a good example of tests which are hard to maintain and - unfortunately - not well defined functions like we happen to have on e.g. database engine unit tests.
> >
> > To recall, when we started with CI some 5 years ago we were in the situation that we had a set of tests, which randomly passed on some dev machines and some on others. So effectively you had no chance to know if a test doesn't pass because of your machine or your patch.
> >
> > At least now we have a reference platform and know if a patch actually does cause changes. Which is the most important information.
> >
> > Currently many of the tests are already cross platform. And nobody is actively writing CI centric tests. It's just a matter of fact that the tests have a requirement to at least pass on the CI env because it's the only thing that can be enforced.
> >
> > When tests are updated to a new platform (ci or not), many of them will pass on a wider variety of platforms. Because bugs are fixed or they are made more generic. And some will just have reference images for one more platform added.
> >
> > So whatever we do we will do a step into the right direction. But there will be no guarantee that every test passes on your machine except if you make them all pass on your machine - which would be very welcome!!
> >
> > What you could also do is listing tests that are generic / platform independent (e.g. the expression tests would be a very good example) and then always just run these instead of the whole set of tests.
>
>
> Just to add a few extra thoughts to the already comprehensive replies
> given by Matthias and Denis:
>
> - we had to do a very similar effort with updating existing tests when
> we moved from Qt 4 -> Qt 5. We'll probably have to do another similar
> effort in another 18-24 months or so. It's going to be a regular,
> recurring task to go through and update all the tests which have been
> introduced since the previous effort and ensure that they are
> sufficiently tolerant to pass under different environments/software
> versions. (Maybe we should consider adding "test maintenance" as a
> regular yearly expense of the nature of 1.5 weeks?)
> - we really should do a similar effort to get the existing tests
> passing under mac os and windows too. I suspect there's some valid
> bugs that the test suites would reveal if we could reliably run them
> under windows/mac, but the real issues are drowned in the noise of
> tests which haven't been designed to be cross platform compatible.
> (This could be a good grant proposal idea for future funding rounds!)
>
> And then my personal 2c:
>
> We have a great test suite, and fantastic tools for making and
> managing tests. Sure, there's a learning curve involved with them.
> Sure, they ARE different to the test suites used by gdal, or geos, or
> <insert other project here>. But that's just business as usual in
> software development, and not at all reflective of inferiority in the
> test suites. Can we please move on from this recurring point once and
> for all and focus on the current relevant parts of this discussion
> instead?
>
> Nyall
>
>


Hi,

While I agree on all points, there is one important thing that we
should make it better while we work on it:
make sure the test suite can **easily** run locally using the same
docker images we are using in the CI process, I can do it but I cannot
say it was easy to set up and it's probably overly complicated for
most people.

Also, making the test suite independent from the particular CI we will
use (GH workflows, Travis & C.) will make it easier to move it to
another CI if needed.

This is of course also a matter of producing a good documentation for
the process and the tools.

Kind regards.

-- 
Alessandro Pasotti
QCooperative:  www.qcooperative.net
ItOpen:   www.itopen.it