{ config, lib, ... }: { imports = [ ./setup-firefox-mock-overlay.nix ]; config = lib.mkIf config.test.enableBig { test.asserts.assertions.expected = ['' Must not have a Firefox profile with an existing ID but - ID 1 is used by first, second'']; programs.firefox = { enable = true; profiles = { first = { isDefault = true; id = 1; }; second = { id = 1; }; }; }; }; }