Unit Test, to verify if AM doesn't use a drained server

TestDrainedServer.java

 /**
   * This is an unit test, to verify if Assignment Manager
   * doesn't use a drained server, comparing number of online region
   * on initial state of the cluster is equal after to put a server 
   * into a drained list.
   * 
   * @throws ServiceException
   * @throws InterruptedException
   * @throws IOException
   * @throws KeeperException
   */
  @Test
  public void testAssignmentManagerDoesntUseDrainingServer() throws ServiceException, InterruptedException, IOException, KeeperException {
    
    HMaster hMaster = TEST_UTIL.getMiniHBaseCluster().getMaster();
    Collection<ServerName> servers = TEST_UTIL.getMiniHBaseCluster().getInitialClusterStatus().getServers();
    Long sizeServedRegions = TEST_UTIL.getMiniHBaseCluster().countServedRegions();
    
    LOG.info("Regions served: " + sizeServedRegions);
    
    AssignmentManager am = hMaster.getAssignmentManager();
    int sizeRegionAssignments = am.getRegionStates().getRegionAssignments().size();
    LOG.info("Size Assigned Regions: " + sizeRegionAssignments);
    
    int randomIndexServer = new Random().nextInt(servers.size());
    ServerName drainedServer = (ServerName) servers.toArray()[randomIndexServer];
    
    LOG.info("Putting Server on Drained List: " + hMaster.getServerManager().addServerToDrainList(drainedServer));
    
    HRegionInfo hri = new HRegionInfo(Bytes.toBytes("table"), 
      HConstants.EMPTY_START_ROW, HConstants.EMPTY_START_ROW, true);
    
    LOG.info("Avaible Servers: " + hMaster.getServerManager().createDestinationServersList().size());
    
    
    Map<HRegionInfo, ServerName> bulkRegion = new HashMap<HRegionInfo, ServerName>();
    bulkRegion.put(hri, drainedServer);
    am.assign(bulkRegion);
    
    am.getRegionStates().waitForAssignment(hri);
    
    
    LOG.info("Creating plan to Drained Server: " + drainedServer.toString());
    RegionPlan planToDrainedServer = new RegionPlan(hri, null, drainedServer);
    am.addPlan(hri.getEncodedName(), planToDrainedServer);
    am.assign(hri, true);
    
    am.getRegionStates().waitForAssignment(hri);
    
    LOG.info("Creating plan to migrate region online to drained server.");
    Map<HRegionInfo, ServerName> regionAssignments = am.getRegionStates().getRegionAssignments();
    int indexAssignedRegionServer = new Random().nextInt(regionAssignments.size());
    HRegionInfo hriAssigned = (HRegionInfo) regionAssignments.keySet().toArray()[indexAssignedRegionServer];
    ServerName serverHriAssigned = regionAssignments.get(hriAssigned);
    RegionPlan planFromOnlineToDrainedServer = new RegionPlan(hriAssigned, serverHriAssigned, drainedServer);
    am.addPlan(hriAssigned.getEncodedName(), planFromOnlineToDrainedServer);
    am.assign(hriAssigned, true);
    
    am.waitForAssignment(hriAssigned);
    
    ServerName drainedRegionServer = am.getRegionStates().getRegionServerOfRegion(hri);
    List<ServerName> destServerList = hMaster.getServerManager().createDestinationServersList();
    
    LOG.info("Server is not in destination Server List");
    assertFalse(destServerList.contains(drainedRegionServer));
    
    int finalSizeRegionAssignment = am.getRegionStates().getRegionAssignments().size();
    assertEquals(sizeRegionAssignments, finalSizeRegionAssignment);  
    
    LOG.info("Initial size assigned regions: " + sizeRegionAssignments);
    LOG.info("Final size assigned regions: " + finalSizeRegionAssignment);

  }