assertSame(
        Ordering.usingToString(),
        ((SortedMap<Integer, Character>) sortedTable.rowMap().values().iterator().next())
            .comparator());
  }

  public void testRowKeySetComparator() {
    sortedTable = TreeBasedTable.create();
    assertSame(Ordering.natural(), sortedTable.rowKeySet().comparator());

    sortedTable = TreeBasedTable.create(Collections.reverseOrder(), Ordering.usingToString());