-# Now reverse the order of sorting
-Net::Z3950::ZOOM::resultset_sort($rs, "dummy", "1=4 >i");
-### There's no way to check for success, as this is a void function
+# Now reverse the order of sorting. We never use resultset_sort(),
+# which is identical to sort1() except that it returns nothing.
+my $status = Net::Z3950::ZOOM::resultset_sort1($rs, "yaz", "1=4>i");
+ok($status < 0, "malformed sort criterion rejected");
+$status = Net::Z3950::ZOOM::resultset_sort1($rs, "yaz", "1=4 >i");
+ok($status == 0, "sort criterion accepted");