Refactor background psql TAP functions

This breaks out the background and interactive psql functionality into a
new class, PostgreSQL::Test::BackgroundPsql.  Sessions are still initiated
via PostgreSQL::Test::Cluster, but once started they can be manipulated by
the new helper functions which intend to make querying easier.  A sample
session for a command which can be expected to finish at a later time can
be seen below.

  my $session = $node->background_psql('postgres');
  $bsession->query_until(qr/start/, q(
    \echo start
	CREATE INDEX CONCURRENTLY idx ON t(a);
  ));
  $bsession->quit;

Patch by Andres Freund with some additional hacking by me.

Author: Andres Freund <andres@anarazel.de>
Reviewed-by: Andrew Dunstan <andrew@dunslane.net>
Discussion: https://postgr.es/m/20230130194350.zj5v467x4jgqt3d6@awork3.anarazel.de

Author: danielgustafsson

contrib/amcheck/t/003_cic_2pc.pl

@@ -36,63 +36,46 @@
 # statements.
 #
 
-my $main_in    = '';
-my $main_out   = '';
-my $main_timer = IPC::Run::timeout($PostgreSQL::Test::Utils::timeout_default);
-
-my $main_h =
-  $node->background_psql('postgres', \$main_in, \$main_out,
-	$main_timer, on_error_stop => 1);
-$main_in .= q(
+my $main_h = $node->background_psql('postgres');
+
+$main_h->query_safe(q(
 BEGIN;
 INSERT INTO tbl VALUES(0);
-\echo syncpoint1
-);
-pump $main_h until $main_out =~ /syncpoint1/ || $main_timer->is_expired;
-
-my $cic_in    = '';
-my $cic_out   = '';
-my $cic_timer = IPC::Run::timeout($PostgreSQL::Test::Utils::timeout_default);
-my $cic_h =
-  $node->background_psql('postgres', \$cic_in, \$cic_out,
-	$cic_timer, on_error_stop => 1);
-$cic_in .= q(
+));
+
+my $cic_h = $node->background_psql('postgres');
+
+$cic_h->query_until(qr/start/, q(
 \echo start
 CREATE INDEX CONCURRENTLY idx ON tbl(i);
-);
-pump $cic_h until $cic_out =~ /start/ || $cic_timer->is_expired;
+));
 
-$main_in .= q(
+$main_h->query_safe(q(
 PREPARE TRANSACTION 'a';
-);
+));
 
-$main_in .= q(
+$main_h->query_safe(q(
 BEGIN;
 INSERT INTO tbl VALUES(0);
-\echo syncpoint2
-);
-pump $main_h until $main_out =~ /syncpoint2/ || $main_timer->is_expired;
+));
 
 $node->safe_psql('postgres', q(COMMIT PREPARED 'a';));
 
-$main_in .= q(
+$main_h->query_safe(q(
 PREPARE TRANSACTION 'b';
 BEGIN;
 INSERT INTO tbl VALUES(0);
-\echo syncpoint3
-);
-pump $main_h until $main_out =~ /syncpoint3/ || $main_timer->is_expired;
+));
 
 $node->safe_psql('postgres', q(COMMIT PREPARED 'b';));
 
-$main_in .= q(
+$main_h->query_safe(q(
 PREPARE TRANSACTION 'c';
 COMMIT PREPARED 'c';
-);
-$main_h->pump_nb;
+));
 
-$main_h->finish;
-$cic_h->finish;
+$main_h->quit;
+$cic_h->quit;
 
 $result = $node->psql('postgres', q(SELECT bt_index_check('idx',true)));
 is($result, '0', 'bt_index_check after overlapping 2PC');
@@ -113,22 +96,15 @@
 ));
 $node->restart;
 
-my $reindex_in  = '';
-my $reindex_out = '';
-my $reindex_timer =
-  IPC::Run::timeout($PostgreSQL::Test::Utils::timeout_default);
-my $reindex_h =
-  $node->background_psql('postgres', \$reindex_in, \$reindex_out,
-	$reindex_timer, on_error_stop => 1);
-$reindex_in .= q(
+my $reindex_h = $node->background_psql('postgres');
+$reindex_h->query_until(qr/start/, q(
 \echo start
 DROP INDEX CONCURRENTLY idx;
 CREATE INDEX CONCURRENTLY idx ON tbl(i);
-);
-pump $reindex_h until $reindex_out =~ /start/ || $reindex_timer->is_expired;
+));
 
 $node->safe_psql('postgres', "COMMIT PREPARED 'spans_restart'");
-$reindex_h->finish;
+$reindex_h->quit;
 $result = $node->psql('postgres', q(SELECT bt_index_check('idx',true)));
 is($result, '0', 'bt_index_check after 2PC and restart');
 

src/bin/psql/t/010_tab_completion.pl

@@ -7,7 +7,6 @@
 use PostgreSQL::Test::Cluster;
 use PostgreSQL::Test::Utils;
 use Test::More;
-use IPC::Run qw(pump finish timer);
 use Data::Dumper;
 
 # Do nothing unless Makefile has told us that the build is --with-readline.
@@ -92,14 +91,7 @@
 close $FH;
 
 # fire up an interactive psql session
-my $in  = '';
-my $out = '';
-
-my $timer = timer($PostgreSQL::Test::Utils::timeout_default);
-
-my $h = $node->interactive_psql('postgres', \$in, \$out, $timer);
-
-like($out, qr/psql/, "print startup banner");
+my $h = $node->interactive_psql('postgres');
 
 # Simple test case: type something and see if psql responds as expected
 sub check_completion
@@ -109,15 +101,12 @@ sub check_completion
 	# report test failures from caller location
 	local $Test::Builder::Level = $Test::Builder::Level + 1;
 
-	# reset output collector
-	$out = "";
 	# restart per-command timer
-	$timer->start($PostgreSQL::Test::Utils::timeout_default);
-	# send the data to be sent
-	$in .= $send;
-	# wait ...
-	pump $h until ($out =~ $pattern || $timer->is_expired);
-	my $okay = ($out =~ $pattern && !$timer->is_expired);
+	$h->{timeout}->start($PostgreSQL::Test::Utils::timeout_default);
+
+	# send the data to be sent and wait for its result
+	my $out = $h->query_until($pattern, $send);
+	my $okay = ($out =~ $pattern && !$h->{timeout}->is_expired);
 	ok($okay, $annotation);
 	# for debugging, log actual output if it didn't match
 	local $Data::Dumper::Terse = 1;
@@ -451,10 +440,7 @@ sub clear_line
 clear_line();
 
 # send psql an explicit \q to shut it down, else pty won't close properly
-$timer->start($PostgreSQL::Test::Utils::timeout_default);
-$in .= "\\q\n";
-finish $h or die "psql returned $?";
-$timer->reset;
+$h->quit or die "psql returned $?";
 
 # done
 $node->stop;