private static boolean validateOnServer() {
    Region<?, ?> region = GemFireCacheImpl.getExisting().getRegion(REGION_NAME1);
    CacheListener<?, ?>[] listeners = region.getAttributes().getCacheListeners();
    for (CacheListener<?, ?> listener : listeners) {
      if (listener instanceof ServerListener) {
        ServerListener serverListener = (ServerListener) listener;
        if (serverListener.afterInvalidateInvoked) {
          return true;
        }
      }
    }
    return false;
  }
1. Invalidate a non-existent entry from the server. 2. Validate that the servers see after
invalidate. 3. Validate that the subscribed client invokes after invalidate.
geode-core/src/distributedTest/java/org/apache/geode/internal/cache/tier/sockets/ClientServerForceInvalidateDUnitTest.java