diff --git a/contrib/test_shm_mq/test.c b/contrib/test_shm_mq/test.c
index 59f18ec..f6b9dd4 100644
--- a/contrib/test_shm_mq/test.c
+++ b/contrib/test_shm_mq/test.c
@@ -13,8 +13,11 @@
 
 #include "postgres.h"
 
+#include <unistd.h>
+
 #include "fmgr.h"
 #include "miscadmin.h"
+#include "storage/ipc.h"
 
 #include "test_shm_mq.h"
 
@@ -72,6 +75,15 @@ test_shm_mq(PG_FUNCTION_ARGS)
 	/* Set up dynamic shared memory segment and background workers. */
 	test_shm_mq_setup(queue_size, nworkers, &seg, &outqh, &inqh);
 
+	/* Try forking a child that immediately exits. */
+	if (fork() == 0)
+	{
+		elog(LOG, "child is PID %d", getpid());
+		on_exit_reset();
+		exit(0);
+	}
+	elog(LOG, "parent is PID %d", getpid());
+
 	/* Send the initial message. */
 	res = shm_mq_send(outqh, message_size, message_contents, false);
 	if (res != SHM_MQ_SUCCESS)