Sample zgy file in Testdata folder
@kvamme3 - Can you please provide some description about available test data sets?
The names include "empty" which leads the reader to think that these do not contain any real data.
Perhaps one good example would be a simple small SegY file and matching ZGY file plus any supplementary information (presumably corner point inline/crossline, X, Y, CRS and whatever else) that is required over and above the raw SegY to make up the Zgy file.