@Test
  public void checkPartitionExpressionProxy() throws MetaException {
    Configuration conf = MetastoreConf.newMetastoreConf();
    HMSHandler hms = new HMSHandler("for testing", conf);
    hms.init();
    Assert.assertEquals(PartitionExpressionForMetastore.class,
        hms.getExpressionProxy().getClass());
  }
Make sure that when HiveMetaStore is instantiated, the default proper PartitionExpressionProxy
instance is instantiated.
itests/hive-unit/src/test/java/org/apache/hadoop/hive/metastore/TestPartitionExpressionProxyDefault.java