Comment 13 for bug 1307180

Why does the shadowing of the search function by yours cause the package-system never to be seen?

Are your search functions trying to return the .asd file for the primary system, and then the actual secondary system never gets found? That's indeed problematic.

Maybe you should put your search functions at the end, but, in these tests, ensure the central-registry and source-registry are empty? Or do you also need them not to be empty?