Add DC_EVENT_SELFAVATAR_CHANGED (#2742)

* Add DC_EVENT_SELFAVATAR_CHANGED

* Add test.

Unfortunately I can't easily also test that the avatar is not copied
from unencrypted messages:

In the second encrypted message, the avatar would not be sent again
then, because we only send avatars once a day or so.

* Unfortunately I can't easily also test that the avatar is not copied from unencrypted messages:

In the second encrypted message, the avatar would not be sent again
then, because we only send avatars once a day or so.

src/test_utils.rs

@@ -34,6 +34,9 @@ use crate::message::{update_msg_state, Message, MessageState, MsgId};
 use crate::mimeparser::MimeMessage;
 use crate::param::{Param, Params};
 
+#[allow(non_upper_case_globals)]
+pub const AVATAR_900x900_BYTES: &[u8] = include_bytes!("../test-data/image/avatar900x900.png");
+
 type EventSink =
     dyn Fn(Event) -> Pin<Box<dyn Future<Output = ()> + Send + 'static>> + Send + Sync + 'static;
 
@@ -587,6 +590,21 @@ impl EvTracker {
             }
         }
     }
+
+    pub async fn get_matching<F: Fn(EventType) -> bool>(&self, event_matcher: F) -> EventType {
+        const TIMEOUT: Duration = Duration::from_secs(20);
+
+        loop {
+            let event = async_std::future::timeout(TIMEOUT, self.recv())
+                .await
+                .unwrap()
+                .unwrap();
+
+            if event_matcher(event.clone()) {
+                return event;
+            }
+        }
+    }
 }
 
 impl Deref for EvTracker {