@Test
  public void testSuccessIncrDumpMetrics() throws Exception {
    ReplicationMetricCollector incrDumpMetricCollector = new IncrementalDumpMetricCollector("db",
        "dummyDir", conf, 0L);
    Map<String, Long> metricMap = new HashMap<>();
    metricMap.put(ReplUtils.MetricName.TABLES.name(), (long) 10);
    metricMap.put(ReplUtils.MetricName.FUNCTIONS.name(), (long) 1);
    incrDumpMetricCollector.reportStageStart("dump", metricMap);
    incrDumpMetricCollector.reportStageProgress("dump", ReplUtils.MetricName.TABLES.name(), 1);
    List<ReplicationMetric> actualMetrics = MetricCollector.getInstance().getMetrics();
    Assert.assertEquals(1, actualMetrics.size());

    incrDumpMetricCollector.reportStageProgress("dump", ReplUtils.MetricName.TABLES.name(), 2);
    incrDumpMetricCollector.reportStageProgress("dump", ReplUtils.MetricName.FUNCTIONS.name(), 1);
    actualMetrics = MetricCollector.getInstance().getMetrics();
    Assert.assertEquals(1, actualMetrics.size());

    incrDumpMetricCollector.reportStageEnd("dump", Status.SUCCESS, 10, new SnapshotUtils.ReplSnapshotCount(),
        new ReplStatsTracker(0));
    incrDumpMetricCollector.reportEnd(Status.SUCCESS);
    actualMetrics = MetricCollector.getInstance().getMetrics();
    Assert.assertEquals(1, actualMetrics.size());

    Metadata expectedMetadata = new Metadata("db", Metadata.ReplicationType.INCREMENTAL, "dummyDir");
    expectedMetadata.setLastReplId(10);
    Progress expectedProgress = new Progress();
    expectedProgress.setStatus(Status.SUCCESS);
    Stage dumpStage = new Stage("dump", Status.SUCCESS, 0);
    dumpStage.setEndTime(0);
    Metric expectedTableMetric = new Metric(ReplUtils.MetricName.TABLES.name(), 10);
    expectedTableMetric.setCurrentCount(3);
    Metric expectedFuncMetric = new Metric(ReplUtils.MetricName.FUNCTIONS.name(), 1);
    expectedFuncMetric.setCurrentCount(1);
    dumpStage.addMetric(expectedTableMetric);
    dumpStage.addMetric(expectedFuncMetric);
    expectedProgress.addStage(dumpStage);
    ReplicationMetric expectedMetric = new ReplicationMetric(1, "repl", 0,
        expectedMetadata);
    expectedMetric.setProgress(expectedProgress);
    checkSuccess(actualMetrics.get(0), expectedMetric, "dump",
        Arrays.asList(ReplUtils.MetricName.TABLES.name(), ReplUtils.MetricName.FUNCTIONS.name()));
  }
Unit Test class for In Memory Replication Metric Collection.
ql/src/test/org/apache/hadoop/hive/ql/parse/repl/metric/TestReplicationMetricCollector.java