{ config, pkgs, ... }: let backups = config.programs.borgmatic.backups; in { programs.borgmatic = { enable = true; backups = { main = { location = { sourceDirectories = [ "/my-stuff-to-backup" ]; patterns = [ "R /" "+ my-stuff-to-backup" ]; repositories = [ "/mnt/disk1" ]; }; }; }; }; test.stubs.borgmatic = { }; test.asserts.assertions.expected = ['' Borgmatic backup configuration "main" cannot specify both 'location.sourceDirectories' and 'location.patterns'. '']; }