add test for deserializing room_member

ruma-client-api/src/r0/membership/joined_members.rs

@@ -68,3 +68,37 @@ impl RoomMember {
         Default::default()
     }
 }
+
+#[cfg(test)]
+mod test {
+    use super::RoomMember;
+    use matches::assert_matches;
+    use serde_json::{from_value as from_json_value, json};
+
+    #[test]
+    fn deserialize_room_member() {
+        assert_matches!(
+            from_json_value::<RoomMember>(json!({
+                "display_name": "alice",
+                "avatar_url": "mxc://localhost:wefuiwegh8742w",
+            })).unwrap(),
+            RoomMember {
+                display_name: Some(display_name),
+                avatar_url: Some(avatar_url),
+            } if display_name == "alice"
+                && avatar_url == "mxc://localhost:wefuiwegh8742w"
+        );
+
+        #[cfg(feature = "compat")]
+        assert_matches!(
+            from_json_value::<RoomMember>(json!({
+                "display_name": "alice",
+                "avatar_url": "",
+            })).unwrap(),
+            RoomMember {
+                display_name: Some(display_name),
+                avatar_url: None,
+            } if display_name == "alice"
+        );
+    }
+}