@Test
  public void testCompactionLog() throws Exception {
    SystemKeyspace.discardCompactionsInProgress();

    String cf = "Standard4";
    ColumnFamilyStore cfs = Keyspace.open(KEYSPACE1).getColumnFamilyStore(cf);
    SchemaLoader.insertData(KEYSPACE1, cf, 0, 1);
    cfs.forceBlockingFlush();

    Collection<SSTableReader> sstables = cfs.getSSTables();
    assertFalse(sstables.isEmpty());
    Set<Integer> generations =
        Sets.newHashSet(
            Iterables.transform(
                sstables,
                new Function<SSTableReader, Integer>() {
                  public Integer apply(SSTableReader sstable) {
                    return sstable.descriptor.generation;
                  }
                }));
    UUID taskId = SystemKeyspace.startCompaction(cfs, sstables);
    Map<Pair<String, String>, Map<Integer, UUID>> compactionLogs =
        SystemKeyspace.getUnfinishedCompactions();
    Set<Integer> unfinishedCompactions = compactionLogs.get(Pair.create(KEYSPACE1, cf)).keySet();
    assertTrue(unfinishedCompactions.containsAll(generations));

    SystemKeyspace.finishCompaction(taskId);
    compactionLogs = SystemKeyspace.getUnfinishedCompactions();
    assertFalse(compactionLogs.containsKey(Pair.create(KEYSPACE1, cf)));
  }
 public void doVerb(MessageIn message, int id) {
   logger.debug("Received migration request from {}.", message.from);
   MessageOut<Collection<RowMutation>> response =
       new MessageOut<>(
           MessagingService.Verb.INTERNAL_RESPONSE,
           SystemKeyspace.serializeSchema(),
           MigrationManager.MigrationsSerializer.instance);
   MessagingService.instance().sendReply(response, id, message.from);
 }