@BeforeClass
  public static void beforeClass() throws IOException {
    // Ensure test dir is created
    HTU.getDataTestDir().getFileSystem(HTU.getConfiguration()).mkdirs(HTU.getDataTestDir());
  }
Make a file for rules that is inside a temporary test dir named for the method so it doesn't
clash w/ other rule files.
hbase-balancer/src/test/java/org/apache/hadoop/hbase/master/balancer/TestStochasticLoadBalancerHeterogeneousCostRules.java