fix: Ensure that message being sent is added to the bottom (#8027)

Before, if the user fixed their clock incorrectly set to the future, they needed to delete
previously sent messages or wait until this future comes again so that new sent messages are added
to the bottom. Strictly speaking, the problem isn't fixable because we don't know if messages were
incorrectly timestamped into the future or they are timestamped correctly and the clock is now
incorrectly set to the past. Anyway, adding messages to the middle of the chat isn't a good way to
inform the user about the problem.

src/chat/chat_tests.rs

@@ -5027,6 +5027,31 @@ async fn test_do_not_overwrite_draft() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_outgoing_msg_after_another_from_future() -> Result<()> {
+    let mut tcm = TestContextManager::new();
+    let t = &tcm.alice().await;
+    let chat_id = t.get_self_chat().await.id;
+
+    // Simulate sending a message with clock set to the future.
+    SystemTime::shift(Duration::from_secs(3600));
+    let msg_id = send_text_msg(t, chat_id, "test".to_string()).await?;
+    SystemTime::shift_back(Duration::from_secs(3600));
+
+    let timestamp_sent: i64 = t
+        .sql
+        .query_get_value("SELECT timestamp_sent FROM msgs WHERE id=?", (msg_id,))
+        .await?
+        .unwrap();
+    // Let's have a check here that locally sent messages have zero `timestamp_sent`, it can be a
+    // useful invariant.
+    assert_eq!(timestamp_sent, 0);
+
+    let msg_id = send_text_msg(t, chat_id, "Fixed my clock".to_string()).await?;
+    assert_eq!(t.get_last_msg_in(chat_id).await.id, msg_id);
+    Ok(())
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_info_contact_id() -> Result<()> {
     let mut tcm = TestContextManager::new();