test that bcc_self-updates are not triggered twice

bcc_self-updates are not received
due to the normal prevention of not even downloading these messages.

there is no extra defense of that on webxdc-level;
status-updates do not even have a "global-unique" id
(they have a local id and the message where they're wrappted into have the
"global-unique" Message-Id)

src/webxdc.rs

@@ -624,6 +624,7 @@ mod tests {
         ProtectionStatus,
     };
     use crate::chatlist::Chatlist;
+    use crate::config::Config;
     use crate::contact::Contact;
     use crate::dc_receive_imf::dc_receive_imf;
     use crate::test_utils::TestContext;
@@ -1065,6 +1066,7 @@ mod tests {
     #[async_std::test]
     async fn test_send_webxdc_status_update() -> Result<()> {
         let alice = TestContext::new_alice().await;
+        alice.set_config_bool(Config::BccSelf, true).await?;
         let bob = TestContext::new_bob().await;
 
         // Alice sends an webxdc instance and a status update
@@ -1146,6 +1148,19 @@ mod tests {
         assert_eq!(alice2_instance.viewtype, Viewtype::Webxdc);
         assert_eq!(alice2_chat_id.get_msg_cnt(&alice2).await?, 1);
 
+        // To support the second device, Alice has enabled bcc_self and will receive their own messages;
+        // these messages, however, should be ignored
+        alice.recv_msg_opt(sent1).await;
+        alice.recv_msg_opt(sent2).await;
+        assert_eq!(alice_chat.id.get_msg_cnt(&alice).await?, 1);
+        assert_eq!(
+            alice
+                .get_webxdc_status_updates(alice_instance.id, StatusUpdateSerial(0))
+                .await?,
+            r#"[{"payload":{"foo":"bar"},"serial":1,"max_serial":2},
+{"payload":{"snipp":"snapp"},"serial":2,"max_serial":2}]"#
+        );
+
         Ok(())
     }