# 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()