private void resetReferenceTopicsAndMessages() {
    refTopics.clear();
    refMessages.clear();
    refTopics.add(UUID.randomUUID().toString());
    refTopics.add(UUID.randomUUID().toString());
    refMessages.add(UUID.randomUUID().toString());
    refMessages.add(UUID.randomUUID().toString());
  }
Resets reference topic list and message list.
ambry-commons/src/test/java/com/github/ambry/commons/HelixNotifierTest.java