xdgAllConfigDirs

auto newConfigHome = "/home/myuser/data";
auto newConfigDirs = ["/usr/local/data", "/usr/data"];

auto homeGuard = EnvGuard("HOME", "");
auto configHomeGuard = EnvGuard("XDG_CONFIG_HOME", newConfigHome);
auto configDirsGuard = EnvGuard("XDG_CONFIG_DIRS", "/usr/local/data:/usr/data");

assert(xdgAllConfigDirs() == newConfigHome ~ newConfigDirs);

environment.remove("XDG_CONFIG_HOME");
environment.remove("HOME");

assert(xdgAllConfigDirs() == newConfigDirs);