table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    Cell<String, Integer, Character> cell = table.cellSet().iterator().next();
    assertEquals(Tables.immutableCell("foo", 1, 'a'), cell);
    assertEquals((Character) 'a', table.put("foo", 1, 'd'));
    assertEquals(Tables.immutableCell("foo", 1, 'd'), cell);
  }

  public void testRowMissing() {

    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    Cell<String, Integer, Character> cell = table.cellSet().iterator().next();
    assertEquals(Tables.immutableCell("foo", 1, 'a'), cell);
    assertEquals((Character) 'a', table.put("foo", 1, 'd'));
    assertEquals(Tables.immutableCell("foo", 1, 'd'), cell);
  }

  public void testRowMissing() {

    ImmutableTable.Builder<Character, Integer, String> builder = new ImmutableTable.Builder<>();

    final StringHolder holder = new StringHolder();
    holder.string = "foo";
    Table.Cell<Character, Integer, String> mutableCell =
        new Tables.AbstractCell<Character, Integer, String>() {
          @Override
          public Character getRowKey() {
            return 'K';
          }