Improve tests

Author: za-arthur

expected/pg_variables.out

@@ -553,6 +553,20 @@ SELECT pgv_insert('vars3', 'r1', row(1, 1));
 ERROR:  new record structure differs from variable "r1" structure
 SELECT pgv_insert('vars3', 'r1', row('str1', 'str1'));
 ERROR:  new record structure differs from variable "r1" structure
+SELECT pgv_select('vars3', 'r1') LIMIT 2;
+ pgv_select 
+------------
+ (,strNULL)
+ (1,str11)
+(2 rows)
+
+SELECT pgv_select('vars3', 'r1') LIMIT 2 OFFSET 2;
+ pgv_select 
+------------
+ (2,)
+ (0,str00)
+(2 rows)
+
 SELECT pgv_select('vars3', 'r1');
  pgv_select 
 ------------

sql/pg_variables.sql

@@ -153,6 +153,9 @@ SELECT pgv_insert('vars3', 'r1', row(1, 'str1', 'str2'));
 SELECT pgv_insert('vars3', 'r1', row(1, 1));
 SELECT pgv_insert('vars3', 'r1', row('str1', 'str1'));
 
+SELECT pgv_select('vars3', 'r1') LIMIT 2;
+SELECT pgv_select('vars3', 'r1') LIMIT 2 OFFSET 2;
+
 SELECT pgv_select('vars3', 'r1');
 SELECT pgv_select('vars3', 'r1', 1);
 SELECT pgv_select('vars3', 'r1', 0);