If you add "test" to FEATURES (well, I always have had it) you'll get a warning: "the test suite should not be run as root" So, if "userpriv" isn't a feature, "test" should be filtered out.
Sorry, Gentoo Linux bug wranglers (and thanks for your patience), I'm trying to assign it to base-system@gentoo.org but I'm unable to do it...
it's a warning, not an error
ok, SpanKY so no need to remove test from make.conf by hand and filter it out, I usually don't ignore test warnings, it doesn't matter; thank you very very much for your time.
usually you only need to pay attention to the tests that cause emerge to abort