Test::Simple 0.82, lib/DB.t is now issuing a warning. His original
suggestion was ok(!defined ...) - he, Merijn and I independently
refined this to isnt(..., undef)
p4raw-id: //depot/perl@34554
# test DB::_clientname()
is( DB::_clientname('foo=A(1)'), 'foo',
'DB::_clientname should return refname');
-cmp_ok( DB::_clientname('bar'), 'eq', '',
+is( DB::_clientname('bar'), undef,
'DB::_clientname should not return non refname');
# test DB::next() and DB::step()