d/d/t/test_data.py: endian independent dtype.

[emollier]

test_sphere_dtypes produces consistently little endian float64 numpy objects. This is usually not an issue, but big endian systems, the little endian value is compared against a big endian float64, causing the test to fail. This fixes/worksaround the test failure on big endian CPUs.

[skoudoro]

Thank you for doing this.

We might need to set up a Github Action with big endian systems to avoid those recurring issue (something using QEMU I suppose, I need to look into it - if you have an example, feel free to share! )

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (24f76c8) 81.91% compared to head (6966cbe) 81.91%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3043   +/-   ##
=======================================
  Coverage   81.91%   81.91%           
=======================================
  Files         147      147           
  Lines       20652    20652           
  Branches     3317     3317           
=======================================
  Hits        16917    16917           
  Misses       2903     2903           
  Partials      832      832           

[emollier]

I don't know how to bind the below on Github Actions, but maybe this will give you ideas.

To test on big endian, my go to platform is to use qemu-system-s390x coupled to binfmt kernel settings, provided by Debian packages qemu-system-misc and qemu-user-static. Once installed, I can spawn a Debian s390x system root tree with e.g.:

# debootstrap --arch s390x sid /srv/chroot/sid-390x http://ftp.fr.debian.org/debian

Once done, I can chroot straight into the tree and, thanks to binfmt, qemu-system-s390x will "interpret" the s390x executables:

# uname -m
x86_64
# chroot /srv/chroot/sid-390x
# uname -m
s390x

Crude yet effective. Main drawback is, that emulation for s390x is slow: running the test suite took some eight hours to run on my machine, to compare to one quarter of hour on the native cpu.

I'm using actually a configuration a bit more elaborate, but you get the idea.

[skoudoro]

all green, merging. I will create an issue to remember the s390x github action (to do later during the year)