var l Level
		err := l.parse(test.in)
		if err == nil || !strings.Contains(err.Error(), test.want) {
			t.Errorf("%q: got %v, want string containing %q", test.in, err, test.want)
		}
	}
}

func TestLevelFlag(t *testing.T) {
	fs := flag.NewFlagSet("test", flag.ContinueOnError)
	lf := LevelInfo
	fs.TextVar(&lf, "level", lf, "set level")
	err := fs.Parse([]string{"-level", "WARN+3"})
	if err != nil {
		t.Fatal(err)