/usr/lib/portage/bin/ebuild.sh issues a warning whenever an ebuild has test as part of its RESTRICT list. Wit ELOG enabled, this causes an email being sent every time, which can get a bit annoying, since I'm not running tests anyway, so I don't really care about them being disabled. It would be nice to swap this test and the following one, i.e. check if test is included in FEATURES, and only if it is, check for restrictions. This would cause an ewarn only if people have activated the test feature.
Thanks for reporting. This is fixed in svn r3389.
This has been released in 2.1_rc2.