--- a/src/test/modules/commit_ts/t/001_base.pl
+++ b/src/test/modules/commit_ts/t/001_base.pl
@@ -11,8 +11,7 @@ use Test::More;
 use PostgreSQL::Test::Cluster;
 
 my $node = PostgreSQL::Test::Cluster->new('foxtrot');
-$node->init;
-$node->append_conf('postgresql.conf', 'track_commit_timestamp = on');
+$node->init(extra => [ '-c', 'track_commit_timestamp=on' ]);
 $node->start;