Hi, > I've abandoned running the tests though, I'm hitting a module not > found error. pytest doesn't manage to load the just built module, > probably an issue with the paths. It's an actual problem with the build. You need to build the cython extension first. I've attached the working package definition. I'd like to add this to gnu/packages/bioinformatics.scm. I'd like to set authorship of the commit to you. Is the name and email address I used for attribution correct? (See the attached commit.) -- Ricardo