exp: useful;
]])
-AT_CHECK([[bison input.y]])
+AT_CHECK([[bison input.y]], 0, [],
+[[input.y contains 9 useless nonterminals
+]])
AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' input.output]], 0,
-[[Terminals which are not used:
+[[Useless nonterminals:
useless1
useless2
useless3