test: Uncomment those tests

lib/src/double_ratchet/double_ratchet.dart

@@ -293,7 +293,11 @@ class OmemoDoubleRatchet {
       return plaintext;
     }
 
-    if (header.dhPub != await dhr?.getBytes()) {
+    final dhPubMatches = listsEqual(
+      header.dhPub ?? <int>[],
+      await dhr?.getBytes() ?? <int>[],
+    );
+    if (!dhPubMatches) {
       await _skipMessageKeys(header.pn!);
       await _dhRatchet(header);
     }

lib/src/omemo/sessionmanager.dart

@@ -387,11 +387,20 @@ class OmemoSessionManager {
     });
   }
 
-  @visibleForTesting
-  OmemoDoubleRatchet getRatchet(String jid, int deviceId) => _ratchetMap[RatchetMapKey(jid, deviceId)]!;
+  /// Returns the device map, i.e. the mapping of bare Jid to its device identifiers
+  /// we have built sessions with.
+  Future<Map<String, List<int>>> getDeviceMap() async {
+    Map<String, List<int>>? map;
+
+    await _lock.synchronized(() async {
+        map = _deviceMap;
+    });
+
+    return map!;
+  }
   
   @visibleForTesting
-  Map<String, List<int>> getDeviceMap() => _deviceMap;
+  OmemoDoubleRatchet getRatchet(String jid, int deviceId) => _ratchetMap[RatchetMapKey(jid, deviceId)]!;
 
   @visibleForTesting
   Map<RatchetMapKey, OmemoDoubleRatchet> getRatchetMap() => _ratchetMap;

test/serialisation_test.dart

@@ -93,7 +93,7 @@ void main() {
     final oldDevice = await oldSession.getDevice();
     final newDevice = await newSession.getDevice();
     expect(await oldDevice.equals(newDevice), true);
-    expect(oldSession.getDeviceMap(), newSession.getDeviceMap());
+    expect(await oldSession.getDeviceMap(), await newSession.getDeviceMap());
 
     expect(oldSession.getRatchetMap().length, newSession.getRatchetMap().length);
     for (final session in oldSession.getRatchetMap().entries) {