The 1904_66*.fits files were downloaded from the web site:

http://www.atnf.csiro.au/people/mcalabre/WCS/example_data.html

Dr. Mark Calabretta gave us (MJ -- private communication) the OK to include 
them in the GalSim distribution, so thanks very much to him for making these
available to us to use for unit tests!  From Mark:

    I'm happy for you to include whichever test files you want with
    the GalSim package.


The files region.fits, sipsample.fits, tnx.fits, tpv.fits, zpx.fits are
the sample files for the corresponding registrations of these WCS FITS
conventions.  They are all in the public domain.  See:

http://fits.gsfc.nasa.gov/fits_registry.html

The file tanpv.fits is just a copy of tpv.fits with the CTYPE tags
changed from TPV to TAN.

The file tanflip.fits is made by the script test_pyast_tpv.py.  It has
the RA, Dec axes flipped relative to the normal ordering, which is apparently
an allowed thing in the FITS standard.

The file DECam_00158414_01.fits.fz is from DES SV observations, and has some header
values with NAN.0 that natively give VerifyWarning's from astropy.  We can now 
handle these kinds of problems seamlessly in GalSim.
