Improve a bit the tests of pg_walinspect

This commit improves the tests of pg_walinspect on a few things:
- Remove aggregates for queries that should fail.  If the code is
reworked in such a way that the behavior of these queries is changed,
we would get more input from them, written this way.
- Expect at least one record reported in the valid queries doing scans
across ranges, rather than zero records.
- Adjust a few comments, for consistency.

Author: Bharath Rupireddy
Discussion: https://postgr.es/m/CALj2ACVaoXW3nJD9zq8E66BEf-phgJfFcKRVJq9GXkuX0b3ULQ@mail.gmail.com

1 files changed, 7 insertions, 6 deletions

diff --git a/contrib/pg_walinspect/sql/oldextversions.sql b/contrib/pg_walinspect/sql/oldextversions.sql
index 1f8307816ef..e35c4f3ed15 100644
--- a/contrib/pg_walinspect/sql/oldextversions.sql
+++ b/contrib/pg_walinspect/sql/oldextversions.sql
@@ -1,4 +1,4 @@
--- test old extension version entry points
+-- Test old extension version entry points.
 
 CREATE EXTENSION pg_walinspect WITH VERSION '1.0';
 
@@ -20,16 +20,17 @@ CREATE TABLE sample_tbl(col1 int, col2 int);
 SELECT pg_current_wal_lsn() AS wal_lsn1 \gset
 INSERT INTO sample_tbl SELECT * FROM generate_series(1, 2);
 
--- Check bounds for these past functions.
+-- Tests for the past functions.
 SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_records_info_till_end_of_wal(:'wal_lsn1');
 SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_stats_till_end_of_wal(:'wal_lsn1');
-SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_records_info_till_end_of_wal('FFFFFFFF/FFFFFFFF');
-SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_stats_till_end_of_wal('FFFFFFFF/FFFFFFFF');
+-- Failures with start LSNs.
+SELECT * FROM pg_get_wal_records_info_till_end_of_wal('FFFFFFFF/FFFFFFFF');
+SELECT * FROM pg_get_wal_stats_till_end_of_wal('FFFFFFFF/FFFFFFFF');
 
--- Move to new version 1.1
+-- Move to new version 1.1.
 ALTER EXTENSION pg_walinspect UPDATE TO '1.1';
 
--- List what version 1.1 contains
+-- List what version 1.1 contains.
 \dx+ pg_walinspect
 
 SELECT pg_drop_replication_slot('regress_pg_walinspect_slot');