Add a test for "ORDER BY DESC"

expected/compare/integer/order_by_limit/desc.out

@@ -0,0 +1,30 @@
+CREATE TABLE ids (
+  id integer
+);
+INSERT INTO ids VALUES (2);
+INSERT INTO ids VALUES (7);
+INSERT INTO ids VALUES (6);
+INSERT INTO ids VALUES (4);
+INSERT INTO ids VALUES (5);
+INSERT INTO ids VALUES (8);
+INSERT INTO ids VALUES (1);
+INSERT INTO ids VALUES (10);
+INSERT INTO ids VALUES (3);
+INSERT INTO ids VALUES (9);
+CREATE INDEX grnindex ON ids USING pgroonga (id);
+SET enable_seqscan = off;
+SET enable_indexscan = on;
+SELECT id
+  FROM ids
+  ORDER BY id DESC
+  LIMIT 5;
+ id 
+----
+ 10
+  9
+  8
+  7
+  6
+(5 rows)
+
+DROP TABLE ids;

sql/compare/integer/order_by_limit/desc.sql

@@ -0,0 +1,26 @@
+CREATE TABLE ids (
+  id integer
+);
+
+INSERT INTO ids VALUES (2);
+INSERT INTO ids VALUES (7);
+INSERT INTO ids VALUES (6);
+INSERT INTO ids VALUES (4);
+INSERT INTO ids VALUES (5);
+INSERT INTO ids VALUES (8);
+INSERT INTO ids VALUES (1);
+INSERT INTO ids VALUES (10);
+INSERT INTO ids VALUES (3);
+INSERT INTO ids VALUES (9);
+
+CREATE INDEX grnindex ON ids USING pgroonga (id);
+
+SET enable_seqscan = off;
+SET enable_indexscan = on;
+
+SELECT id
+  FROM ids
+  ORDER BY id DESC
+  LIMIT 5;
+
+DROP TABLE ids;