@After
  public void after() throws Exception {
    UTIL.shutdownMiniCluster();
  }
Test whether region re-balancing works. (HBASE-71) The test only works for cluster wide
balancing, not per table wide. Increase the margin a little to make StochasticLoadBalancer result
acceptable.
hbase-server/src/test/java/org/apache/hadoop/hbase/TestRegionRebalancing.java