public static Comparator<Object[]> getComparator(List<OrderByExpressionContext> orderByExpressions,
      ColumnContext[] orderByColumnContexts, boolean nullHandlingEnabled) {
    return getComparator(orderByExpressions, orderByColumnContexts, nullHandlingEnabled, 0, orderByExpressions.size());
  }
@Test
  public void testAscNullsLast() {
    List<OrderByExpressionContext> orderBys =
        Collections.singletonList(new OrderByExpressionContext(COLUMN1, ASC, NULLS_LAST));
    setUpSingleColumnRows();

    _rows.sort(OrderByComparatorFactory.getComparator(orderBys, ENABLE_NULL_HANDLING));

    assertEquals(extractColumn(_rows, COLUMN1_INDEX), Arrays.asList(1, 2, null));
  }