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<>();

    assertEquals(
        ImmutableTable.of('a', 1, "foo"), builder.put(Tables.immutableCell('a', 1, "foo")).build());
  }

  public void testBuilder_withImmutableCellAndNullContents() {
    ImmutableTable.Builder<Character, Integer, String> builder = new ImmutableTable.Builder<>();
    try {
      builder.put(Tables.immutableCell((Character) null, 1, "foo"));
      fail();
    } catch (NullPointerException e) {