assertEquals((Character) 'b', table.get("bar", 1));
    assertSize(3);
    assertEquals((Character) 'd', table.put("foo", 1, cellValue('d')));
    assertEquals((Character) 'd', table.get("foo", 1));
    assertSize(3);
  }

  public void testPutNull() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    assertSize(3);

    assertEquals((Character) 'b', table.get("bar", 1));
    assertSize(3);
    assertEquals((Character) 'd', table.put("foo", 1, cellValue('d')));
    assertEquals((Character) 'd', table.get("foo", 1));
    assertSize(3);
  }

  public void testPutNull() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    assertSize(3);

  public void testNullPointerInstance() {}

  // put() and putAll() aren't supported.
  @Override
  public void testPut() {
    assertThrows(UnsupportedOperationException.class, () -> table.put("foo", 1, 'a'));
    assertSize(0);
  }

  @Override
  public void testPutAllTable() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    Table<String, Integer, Character> other = HashBasedTable.create();

    assertTrue(table.isEmpty());
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    assertFalse(table.isEmpty());
  }

  public void testSize() {
    assertSize(0);
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    assertSize(3);
  }

  public void testEquals() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    // We know that we have only added non-null Characters.