Tables.immutableCell(null, null, null);
    assertEquals("(null,null)=null", nullEntry.toString());
  }

  public void testEntryEquals() {
    Cell<String, Integer, Character> entry = Tables.immutableCell("foo", 1, 'a');

    new EqualsTester()
        .addEqualityGroup(entry, Tables.immutableCell("foo", 1, 'a'))
        .addEqualityGroup(Tables.immutableCell("bar", 1, 'a'))
        .addEqualityGroup(Tables.immutableCell("foo", 2, 'a'))

                    return new SampleElements<>(
                        Tables.immutableCell("bar", 1, 'a'),
                        Tables.immutableCell("bar", 2, 'b'),
                        Tables.immutableCell("bar", 3, (Character) null),
                        Tables.immutableCell("bar", 4, 'b'),
                        Tables.immutableCell("bar", 5, 'b'));
                  }

                  @Override

                .put("two", "dos", 6)
                .put("three", "tres", 3)
                .build(),
            immutableCell("one", "uno", 1),
            immutableCell("two", "dos", 2),
            immutableCell("three", "tres", 3),
            immutableCell("two", "dos", 4));
  }

  public void testToImmutableTableMergingNullRowKey() {

        Tables.immutableCell(null, null, null);
    assertEquals("(null,null)=null", nullEntry.toString());
  }

  public void testEntryEquals() {
    Cell<String, Integer, Character> entry = Tables.immutableCell("foo", 1, 'a');

    new EqualsTester()
        .addEqualityGroup(entry, Tables.immutableCell("foo", 1, 'a'))
        .addEqualityGroup(Tables.immutableCell("bar", 1, 'a'))
        .addEqualityGroup(Tables.immutableCell("foo", 2, 'a'))

  private static final ImmutableSet<Cell<Character, Integer, String>> CELLS =
      ImmutableSet.of(
          Tables.immutableCell('a', 1, "foo"),
          Tables.immutableCell('b', 1, "bar"),
          Tables.immutableCell('a', 2, "baz"));

  private static final ImmutableSet<Character> ROW_SPACE = ImmutableSet.of('a', 'b');

  private static final ImmutableSet<Cell<Character, Integer, String>> CELLS =
      ImmutableSet.of(
          Tables.immutableCell('a', 1, "foo"),
          Tables.immutableCell('b', 1, "bar"),
          Tables.immutableCell('a', 2, "baz"));

  private static final ImmutableSet<Character> ROW_SPACE = ImmutableSet.of('a', 'b');

                    return new SampleElements<>(
                        Tables.immutableCell("bar", 1, 'a'),
                        Tables.immutableCell("bar", 2, 'b'),
                        Tables.immutableCell("bar", 3, (Character) null),
                        Tables.immutableCell("bar", 4, 'b'),
                        Tables.immutableCell("bar", 5, 'b'));
                  }

                  @Override

    CollectorTester.of(collector)
        .expectCollects(ImmutableTable.of())
        .expectCollects(
            ImmutableTable.of("one", "uno", 3),
            Tables.immutableCell("one", "uno", 1),
            Tables.immutableCell("one", "uno", 2));
  }

  public void testBuilder() {
    ImmutableTable.Builder<Character, Integer, String> builder = new ImmutableTable.Builder<>();

  public void testHashCode() {
    assertEquals(Objects.hashCode('a', 1, "blah"), testTable.hashCode());
  }

  public void testCellSet() {
    assertEquals(ImmutableSet.of(Tables.immutableCell('a', 1, "blah")), testTable.cellSet());
  }

  public void testColumn() {
    assertEquals(ImmutableMap.of(), testTable.column(0));
    assertEquals(ImmutableMap.of('a', "blah"), testTable.column(1));
  }

      if (cell instanceof Tables.ImmutableCell) {
        checkNotNull(cell.getRowKey(), "row");
        checkNotNull(cell.getColumnKey(), "column");
        checkNotNull(cell.getValue(), "value");
        @SuppressWarnings("unchecked") // all supported methods are covariant
        Cell<R, C, V> immutableCell = (Cell<R, C, V>) cell;
        cells.add(immutableCell);
      } else {