@VisibleForTesting
  public List<PlacementRule> getPlacementRules() {
    return rules;
  }
@Test
  public void testPlacementRuleUpdationOrder() throws Exception {
    List<QueueMapping> queueMappings = new ArrayList<>();
    QueueMapping userQueueMapping = QueueMappingBuilder.create()
        .type(MappingType.USER).source(USER1)
        .queue(getQueueMapping(PARENT_QUEUE, USER1)).build();

    CSMappingPlacementRule ugRule = new CSMappingPlacementRule();

    conf.set(YarnConfiguration.QUEUE_PLACEMENT_RULES, ugRule.getName());
    queueMappings.add(userQueueMapping);
    conf.setQueueMappings(queueMappings);

    mockRM = new MockRM(conf);
    CapacityScheduler cs = (CapacityScheduler) mockRM.getResourceScheduler();
    mockRM.start();
    PlacementManager pm = cs.getRMContext().getQueuePlacementManager();

    // As we are setting placement rule, It shouldn't update default
    // placement rule ie user-group. Number of placement rules should be 1.
    Assert.assertEquals(1, pm.getPlacementRules().size());
    // Verifying if placement rule set is same as the one we configured
    Assert.assertEquals(ugRule.getName(),
        pm.getPlacementRules().get(0).getName());
  }