diff --git a/src/test/subscription/t/015_stream.pl b/src/test/subscription/t/015_stream.pl
index 7bc342d211..220ab0c25f 100644
--- a/src/test/subscription/t/015_stream.pl
+++ b/src/test/subscription/t/015_stream.pl
@@ -8,8 +8,8 @@ use PostgreSQL::Test::Cluster;
 use PostgreSQL::Test::Utils;
 use Test::More;
 
-# Check the log that the streamed transaction was completed successfully
-# reported by parallel apply worker.
+# Check that the parallel apply worker has finished applying the streaming
+# transaction.
 sub check_parallel_log
 {
 	my ($node_subscriber, $offset, $is_parallel, $type) = @_;
@@ -22,9 +22,7 @@ sub check_parallel_log
 	}
 }
 
-# Encapsulate all the common test steps which are related to "streaming"
-# parameter so the same code can be run both for the streaming=on and
-# streaming=parallel cases.
+# Common test steps for both the streaming=on and streaming=parallel cases.
 sub test_streaming
 {
 	my ($node_publisher, $node_subscriber, $appname, $is_parallel) = @_;
@@ -40,10 +38,8 @@ sub test_streaming
 	my $h = $node_publisher->background_psql('postgres', \$in, \$out, $timer,
 		on_error_stop => 0);
 
-	# If "streaming" parameter is specified as "parallel", we need to check
-	# that streamed transaction was applied using a parallel apply worker.
-	# We have to look for the DEBUG1 log messages about that, so bump up the
-	# log verbosity.
+	# We need to check DEBUG logs to ensure that the parallel apply worker has
+	# applied the transaction. So, bump up the log verbosity.
 	if ($is_parallel)
 	{
 		$node_subscriber->append_conf('postgresql.conf',
@@ -222,6 +218,8 @@ $node_publisher->poll_query_until('postgres',
 
 test_streaming($node_publisher, $node_subscriber, $appname, 1);
 
+# Test that the deadlock is detected among leader and parallel apply workers.
+
 $node_subscriber->append_conf('postgresql.conf', "log_min_messages = debug1");
 $node_subscriber->append_conf('postgresql.conf', "deadlock_timeout = 1ms");
 $node_subscriber->reload;