assertFalse(optionalName.isPresent());
  }

  public void testOf() {
    assertEquals("training", Optional.of("training").get());
  }

  public void testOf_null() {
    assertThrows(NullPointerException.class, () -> Optional.of(null));
  }

  public void testFromNullable() {
    Optional<String> optionalName = Optional.fromNullable("bob");
    assertEquals("bob", optionalName.get());
  }

   * input element is mapped to one cell in the returned table, with the rows, columns, and values
   * generated by applying the specified functions.
   *
   * <p>The returned {@code Collector} will throw a {@code NullPointerException} at collection time
   * if the row, column, or value functions return null on any input.
   *
   * @since 21.0
   */
  public static <T extends @Nullable Object, R, C, V>

    List<Object> list = new ArrayList<>(equalityGroup.length);
    for (int i = 0; i < equalityGroup.length; i++) {
      Object element = equalityGroup[i];
      if (element == null) {
        throw new NullPointerException("at index " + i);
      }
      list.add(element);
    }
    equalityGroups.add(list);
    return this;
  }

  /** Run tests on equals method, throwing a failure on an invalid test */

    expectContents(createArrayWithNullKey());
  }

  @MapFeature.Require(absent = ALLOWS_NULL_KEYS)
  @CollectionSize.Require(absent = ZERO)
  public void testCreateWithNullKeyUnsupported() {
    assertThrows(NullPointerException.class, () -> initMapWithNullKey());
  }

  @MapFeature.Require(ALLOWS_NULL_VALUES)
  @CollectionSize.Require(absent = ZERO)
  public void testCreateWithNullValueSupported() {
    initMapWithNullValue();

  public void testRemove_nullNotSupported() {
    try {
      assertFalse(
          "remove(null) should return false or throw NullPointerException",
          collection.remove(null));
    } catch (NullPointerException tolerated) {
    }
    expectUnchanged();
  }

  @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_QUERIES})
  public void testRemove_nullAllowed() {

          .put(IndexOutOfBoundsException.class, e -> e instanceof IndexOutOfBoundsException)
          .put(NoSuchElementException.class, e -> e instanceof NoSuchElementException)
          .put(NullPointerException.class, e -> e instanceof NullPointerException)
          .put(NumberFormatException.class, e -> e instanceof NumberFormatException)
          .put(RuntimeException.class, e -> e instanceof RuntimeException)

          .put(IndexOutOfBoundsException.class, e -> e instanceof IndexOutOfBoundsException)
          .put(NoSuchElementException.class, e -> e instanceof NoSuchElementException)
          .put(NullPointerException.class, e -> e instanceof NullPointerException)
          .put(NumberFormatException.class, e -> e instanceof NumberFormatException)
          .put(RuntimeException.class, e -> e instanceof RuntimeException)

          .put(IndexOutOfBoundsException.class, e -> e instanceof IndexOutOfBoundsException)
          .put(NoSuchElementException.class, e -> e instanceof NoSuchElementException)
          .put(NullPointerException.class, e -> e instanceof NullPointerException)
          .put(NumberFormatException.class, e -> e instanceof NumberFormatException)
          .put(RuntimeException.class, e -> e instanceof RuntimeException)

          .put(IndexOutOfBoundsException.class, e -> e instanceof IndexOutOfBoundsException)
          .put(NoSuchElementException.class, e -> e instanceof NoSuchElementException)
          .put(NullPointerException.class, e -> e instanceof NullPointerException)
          .put(NumberFormatException.class, e -> e instanceof NumberFormatException)
          .put(RuntimeException.class, e -> e instanceof RuntimeException)

  }

  // This test assumes that the implementation does not support null keys.
  public void testRowNull() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    assertThrows(NullPointerException.class, () -> table.row(null));
  }

  public void testColumn() {
    table = create("foo", 1, 'a', "bar", 1, 'b', "foo", 3, 'c');
    assertEquals(ImmutableMap.of("foo", 'a', "bar", 'b'), table.column(1));