1 files changed, 35 insertions, 0 deletions
diff --git a/src/test/regress/sql/regex.sql b/src/test/regress/sql/regex.sql
index c59fa35f24d..d3030af295d 100644
--- a/src/test/regress/sql/regex.sql
+++ b/src/test/regress/sql/regex.sql
@@ -25,6 +25,41 @@ select substring('asd TO foo' from ' TO (([a-z0-9._]+|"([^"]+|"")+")+)');
 select substring('a' from '((a))+');
 select substring('a' from '((a)+)');
 
+-- Test lookahead constraints
+select regexp_matches('ab', 'a(?=b)b*');
+select regexp_matches('a', 'a(?=b)b*');
+select regexp_matches('abc', 'a(?=b)b*(?=c)c*');
+select regexp_matches('ab', 'a(?=b)b*(?=c)c*');
+select regexp_matches('ab', 'a(?!b)b*');
+select regexp_matches('a', 'a(?!b)b*');
+select regexp_matches('b', '(?=b)b');
+select regexp_matches('a', '(?=b)b');
+
+-- Test lookbehind constraints
+select regexp_matches('abb', '(?<=a)b*');
+select regexp_matches('a', 'a(?<=a)b*');
+select regexp_matches('abc', 'a(?<=a)b*(?<=b)c*');
+select regexp_matches('ab', 'a(?<=a)b*(?<=b)c*');
+select regexp_matches('ab', 'a*(?<!a)b*');
+select regexp_matches('ab', 'a*(?<!a)b+');
+select regexp_matches('b', 'a*(?<!a)b+');
+select regexp_matches('a', 'a(?<!a)b*');
+select regexp_matches('b', '(?<=b)b');
+select regexp_matches('foobar', '(?<=f)b+');
+select regexp_matches('foobar', '(?<=foo)b+');
+select regexp_matches('foobar', '(?<=oo)b+');
+
+-- Test optimization of single-chr-or-bracket-expression lookaround constraints
+select 'xz' ~ 'x(?=[xy])';
+select 'xy' ~ 'x(?=[xy])';
+select 'xz' ~ 'x(?![xy])';
+select 'xy' ~ 'x(?![xy])';
+select 'x'  ~ 'x(?![xy])';
+select 'xyy' ~ '(?<=[xy])yy+';
+select 'zyy' ~ '(?<=[xy])yy+';
+select 'xyy' ~ '(?<![xy])yy+';
+select 'zyy' ~ '(?<![xy])yy+';
+
 -- Test conversion of regex patterns to indexable conditions
 explain (costs off) select * from pg_proc where proname ~ 'abc';
 explain (costs off) select * from pg_proc where proname ~ '^abc';