Fix race condition in the PostgresChannelMessageTableSubscriberTests

Adding two messages into a group may end up with wrong insert order.
Or better to say the timestamp of first messages inserted might be behind in the future after the second one.
This leads to a wrong order return for polling operation and, therefore, verification in the test.

* Fix `PostgresChannelMessageTableSubscriberTests` inserting `Thread.sleep(100);`
between `messageStore.addMessageToGroup()` operations

Author: artembilan

spring-integration-jdbc/src/test/java/org/springframework/integration/jdbc/postgres/PostgresChannelMessageTableSubscriberTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022-2024 the original author or authors.
+ * Copyright 2022-2025 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -88,7 +88,6 @@ CREATE FUNCTION INT_CHANNEL_MESSAGE_NOTIFY_FCT()
 			$BODY$
 			LANGUAGE PLPGSQL;
 			^^^ END OF SCRIPT ^^^
-
 			CREATE TRIGGER INT_CHANNEL_MESSAGE_NOTIFY_TRG
 				AFTER INSERT ON INT_CHANNEL_MESSAGE
 				FOR EACH ROW
@@ -150,6 +149,8 @@ public void testMessagePollMessagesAddedAfterStart() throws Exception {
 			latch.countDown();
 		});
 		messageStore.addMessageToGroup(groupId, new GenericMessage<>("1"));
+		// A little delay to avoid race condition with CREATED_DATE value
+		Thread.sleep(100);
 		messageStore.addMessageToGroup(groupId, new GenericMessage<>("2"));
 		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
 		assertThat(payloads).containsExactly("1", "2");
@@ -165,6 +166,8 @@ public void testMessagePollMessagesAddedBeforeStart() throws InterruptedExceptio
 			latch.countDown();
 		});
 		messageStore.addMessageToGroup(groupId, new GenericMessage<>("1"));
+		// A little delay to avoid race condition with CREATED_DATE value
+		Thread.sleep(100);
 		messageStore.addMessageToGroup(groupId, new GenericMessage<>("2"));
 		postgresChannelMessageTableSubscriber.start();
 		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
@@ -189,6 +192,8 @@ void testMessagesDispatchedInTransaction() throws InterruptedException {
 		postgresSubscribableChannel.subscribe(messageHandler);
 
 		messageStore.addMessageToGroup(groupId, new GenericMessage<>("1"));
+		// A little delay to avoid race condition with CREATED_DATE value
+		Thread.sleep(100);
 		messageStore.addMessageToGroup(groupId, new GenericMessage<>("2"));
 
 		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
@@ -294,6 +299,8 @@ public void testRenewConnection() throws Exception {
 		assertThat(connectionLatch.await(10, TimeUnit.SECONDS)).isTrue();
 
 		messageStore.addMessageToGroup(groupId, new GenericMessage<>("1"));
+		// A little delay to avoid race condition with CREATED_DATE value
+		Thread.sleep(100);
 		messageStore.addMessageToGroup(groupId, new GenericMessage<>("2"));
 		assertThat(latch.await(10, TimeUnit.SECONDS)).isTrue();
 		assertThat(payloads).containsExactlyInAnyOrder("1", "2");