diff --git a/src/bin/pg_upgrade/TESTING b/src/bin/pg_upgrade/TESTING
index 127dc30bbb..98286231d7 100644
--- a/src/bin/pg_upgrade/TESTING
+++ b/src/bin/pg_upgrade/TESTING
@@ -17,6 +17,21 @@ the creation of the dump):
 export olddump=...somewhere/dump.sql	(old version's dump)
 export oldinstall=...otherversion/	(old version's install base path)
 
+"filter_rules" is a variable that can be used to specify a file with custom
+filtering rules applied before comparing the dumps of the PostgreSQL
+instances near the end of the tests, in the shape of regular expressions
+valid for perl.  This is useful to enforce certain validation cases where
+pg_dump could create inconsistent outputs across major versions.
+For example:
+
+	# Remove all CREATE POLICY statements
+	s/^CREATE\sPOLICY.*//mgx
+	# Replace REFRESH with DROP for materialized views
+	s/^REFRESH\s(MATERIALIZED\sVIEW)/DROP $1/mgx
+
+Lines beginning with '#' and empty lines are ignored.  One rule can be
+defined per line.
+
 Finally, the tests can be done by running
 
 	make check
diff --git a/src/bin/pg_upgrade/t/002_pg_upgrade.pl b/src/bin/pg_upgrade/t/002_pg_upgrade.pl
index 4cc1469306..c066fd7d93 100644
--- a/src/bin/pg_upgrade/t/002_pg_upgrade.pl
+++ b/src/bin/pg_upgrade/t/002_pg_upgrade.pl
@@ -45,6 +45,31 @@ sub filter_dump
 	# Remove empty lines.
 	$dump_contents =~ s/^\n//mgx;
 
+	# Apply custom filtering rules, if any.
+	if (defined($ENV{filter_rules}))
+	{
+		my $filter_file = $ENV{filter_rules};
+		die "no file with custom filter rules found!" unless -e $filter_file;
+
+		open my $filter_handle, '<', $filter_file
+		  or die "could not open $filter_file";
+		while (<$filter_handle>)
+		{
+			my $filter_line = $_;
+
+			# Skip comments and empty lines
+			next if ($filter_line =~ /^#/);
+			next if ($filter_line =~ /^\s*$/);
+
+			# Apply lines with filters.
+			note "Applying custom rule $filter_line to $dump_file";
+			my $filter = "\$dump_contents =~ $filter_line";
+			## no critic (ProhibitStringyEval)
+			eval $filter;
+		}
+		close $filter_handle;
+	}
+
 	my $dump_file_filtered = "${dump_file}_filtered";
 	open(my $dh, '>', $dump_file_filtered)
 	  || die "opening $dump_file_filtered";