test 61 fails because 'mail' group doesn't exist on host(hardened uClibc)

[ghost]

TEST 61: textual user/group id
device '/devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/block/sda' expecting node/link 'node'
libudev: add_gid: specified group 'mail' unknown
Argument "mail" isn't numeric in numeric ne (!=) at /var/tmp/portage/sys-fs/eudev-2.1.1/work/eudev-2.1.1/test/
udev-test.pl line 1357.                                                                                         expected permissions are: root:mail:0660
  created permissions are : 0:0:0600
permissions: error
add:         ok
libudev: add_gid: specified group 'mail' unknown
remove:      ok

https://github.com/gentoo/eudev/blob/d7447bb0baa871b5866785ed3ecdfdc35976d458/test/udev-test.pl#L591

To reproduce, with stage3-amd64-uclibc-hardened-20150105.tar.bz2 (chrooted from installCD install-amd64-minimal-20141204.iso)
FEATURES='test' emerge -a '>=sys-fs/eudev-2.1'
[ebuild U ~] sys-fs/eudev-2.1.1 [1.10-r2] USE="{test*}"

this passes correctly if I do: groupadd mail before emerging (tested to work, also groupdel mail afterwards was tested to not work again)
Maybe mail can become something that exists for sure like nogroup, I would say root but that's also a user as well as a group and it's not as distinctive as nogroup would be to ensure test passes because it chose a group rather than due to some unlikely bug it chose a user(if root is used for the group).
I have tested this to work with nogroup (make recheck)

Maybe the tests shouldn't use the system's /etc/ or I am missing something(like sandboxing still happens but it copies/emulates the existing /etc/).

Thanks.

[blueness]

Thanks for the report. This is probably one of those failures we can live with. I don't want to add a mail group to the stage3 and I don't want to remove the test because most systems have a mail group. Let's just leave this issue open as a reminder of the issue.