IndexRowKeyBuilder { public IndexRowKeyBuilder withSortOrder(SortOrder order) { checkNotNull(order, "Order must not be null"); this.order = order; return this; } private  IndexRowKeyBuilder(); static IndexRowKeyBuilder newBuilder(long tableId,
                                                long indexId); IndexRowKeyBuilder withSortOrder(SortOrder order); IndexRowKeyBuilder withRow(Row row,
                                      String indexName,
                                      TableSchema tableSchema); IndexRowKeyBuilder withQueryKey(QueryKey queryKey,
                                           TableSchema tableSchema); IndexRowKeyBuilder withUUID(UUID uuid); IndexRowKey build();  }
@Test(expected = NullPointerException.class) public void testBuilderNullSortOrder() { builder.withSortOrder(null); }
@Test public void testBuilderSortOrder() { assertNotNull(builder.withSortOrder(SortOrder.Descending)); }