@Test
  public void testRandomAssignment() throws Exception {
    for (int i = 1; i != 5; ++i) {
      LOG.info("run testRandomAssignment() with idle servers:" + i);
      testRandomAssignment(i);
    }
  }
Test the cluster startup bulk assignment which attempts to retain assignment info.
hbase-balancer/src/test/java/org/apache/hadoop/hbase/master/balancer/TestBaseLoadBalancer.java