@Test
  public void testUNDEFINED() throws Exception {
    Query q = CacheUtils.getQueryService().newQuery(" UNDEFINED IN SET(1,2,3)");
    Object result = q.execute();
    assertThat(result).isEqualTo(FALSE);

    q = CacheUtils.getQueryService().newQuery(" UNDEFINED IN SET(UNDEFINED)");
    result = q.execute();
    assertThat(result).isEqualTo(QueryService.UNDEFINED);

    q = CacheUtils.getQueryService().newQuery(" UNDEFINED IN SET(UNDEFINED,UNDEFINED)");
    result = q.execute();
    assertThat(result).isEqualTo(QueryService.UNDEFINED);
  }
Test the decomposition of IN SET(..) that gets decomposed into ORs so an index can be used
geode-core/src/integrationTest/java/org/apache/geode/cache/query/functional/INOperatorJUnitTest.java