### Question:
StatisticDataCollectionHelper { public static List<Integer> getParentList(MessageContext messageContext) { Object parentList = messageContext.getProperty(StatisticsConstants.MEDIATION_FLOW_STATISTICS_PARENT_LIST); if (parentList != null) { messageContext.setProperty(StatisticsConstants.MEDIATION_FLOW_STATISTICS_PARENT_LIST, new LinkedList<>()); return (List<Integer>) parentList; } else { return null; } }  static String getStatisticTraceId(MessageContext messageContext); static int getFlowPosition(MessageContext messageContext); static int getParentFlowPosition(MessageContext messageContext, Integer newParentIndex); static List<Integer> getParentList(MessageContext messageContext); static boolean isOutOnlyFlow(MessageContext messageContext); static void collectData(MessageContext messageContext, boolean isContentAltering,
	                               Boolean isCollectingTracing, StatisticDataUnit statisticDataUnit); static void collectAggregatedParents(List<MessageContext> messages, MessageContext newCtx);  }### Answer:
@Test public void testGetParentList() { Assert.assertNull("should return null since no list added", StatisticDataCollectionHelper.getParentList(messageContext)); List<Integer> parentList = Arrays.asList(1, 2, 3); messageContext.setProperty(StatisticsConstants.MEDIATION_FLOW_STATISTICS_PARENT_LIST, parentList); Assert.assertEquals("should return the added parentList", parentList, StatisticDataCollectionHelper.getParentList(messageContext)); }