[Qgis-developer] Continuous Integration / Testing with TravisCI

[Matthias Kuhn]

Hi Even

On 18.11.2014 16:13, Even Rouault wrote:
> Matthias,
>
> Great move from yours !
>
> I can point you to an email I sent to the mapguide folks recently, sharing my 
> experience with C.I. tools for GDAL. See the end of 
> http://lists.osgeo.org/pipermail/mapguide-internals/2014-August/007518.html
Definitely an interesting read. Good to know that ther's a short timeout
with appveyor and alternatives, although mingw/wine solutions appear to
be a workaround. I wonder if there is a problem with appveyor, maybe
there is somebody in need of stable windows build who could sponsor this.
>
> I'm skeptical you'll manage to build QGIS with (the free program of) AppVeyor, 
> since GDAL reaches their build time limit.
>
> Regarding comparing images, MapServer used to use the 'perceptualdiff' utility 
> that can accept some, invisible to the eye, differences between the reference 
> image and the image produced. But this may be sometimes still be a bit 
> oversensitive. Definitely a tricky subject to have rendering tests running 
> consistently accross platforms.
> You mention comparing WKT, but that can be non obvious too since there might 
> be different rounding accross platforms. Better to have a dedicated geometry 
> comparison method that accept an epsilon when doing vertex comparisons.
I had a short look at that last week and found that in the end you still
need to define a number of allowed mismatch pixels for some font images
I compared. But maybe one could tweak the parameters.
Concerning WKT you are right of course (thinking of ARM where qReal is
interpreted as float vs. double on other platforms). Something like this
for vertex comparisons could be good:
https://docs.python.org/2/library/unittest.html#unittest.TestCase.assertAlmostEqual

Matthias