@Test
  public void testIndexMaintenanceWithIndexOnMethodKeys() throws Exception {
    Index i1 = qs.createIndex("indx1", IndexType.FUNCTIONAL, "ks.toString",
        SEPARATOR + "portfolio.keys() ks");
    CacheUtils.getCache();
    region = CacheUtils.getRegion(SEPARATOR + "portfolio");
    region.put("4", new Portfolio(4));
    region.put("5", new Portfolio(5));
    CompactRangeIndex ri = (CompactRangeIndex) i1;
    validateIndexForKeys(ri);
  }
Tests Index maintenance on method Keys() as iterator ( with focus on behaviour if not
implemented in DummyQRegion
geode-core/src/integrationTest/java/org/apache/geode/cache/query/internal/index/IndexMaintenanceJUnitTest.java