Relax timing requirement in MongoEventSourceITAssertions.

Signed-off-by: Yufei Cai <yufei.cai@bosch.io>

services/utils/persistence/src/test/java/org/eclipse/ditto/services/utils/persistence/mongo/ops/eventsource/MongoEventSourceITAssertions.java

@@ -20,6 +20,8 @@
 import java.util.List;
 import java.util.Random;
 import java.util.UUID;
+import java.util.concurrent.CompletionException;
+import java.util.concurrent.TimeUnit;
 
 import org.eclipse.ditto.model.base.entity.id.DefaultEntityId;
 import org.eclipse.ditto.model.base.entity.id.EntityId;
@@ -293,10 +295,12 @@ private void purgeEntities(final Config config, final boolean prependNamespace)
             underTest.tell(purgeEntities, getRef());
             expectMsg(Duration.ofSeconds(8), PurgeEntitiesResponse.successful(entityType, dittoHeaders));
 
+            sleep(Duration.ofSeconds(5L));
+
             // restart the actors for the purged entities - they should work as if its entity never existed
             final ActorRef purgedActor1 = watch(startEntityActor(actorSystem, pubSubMediator, purgedId1));
             purgedActor1.tell(getRetrieveEntityCommand(purgedId1), getRef());
-            expectMsgClass(getEntityNotAccessibleClass());
+            expectMsgClass(Duration.ofSeconds(10L), getEntityNotAccessibleClass());
 
             final ActorRef purgedActor2 = watch(startEntityActor(actorSystem, pubSubMediator, purgedId2));
             purgedActor2.tell(getRetrieveEntityCommand(purgedId2), getRef());
@@ -327,4 +331,12 @@ private static String prependNamespace(final String id, final String ns, final b
         }
     }
 
+    private static void sleep(final Duration duration) {
+        try {
+            TimeUnit.MILLISECONDS.sleep(duration.toMillis());
+        } catch (final Exception e) {
+            throw new CompletionException(e);
+        }
+    }
+
 }