* element, and the overall size of the collection, by one.
   *
   * <p>To both add the element and obtain the previous count of that element, use {@link
   * #add(Object, int) add}{@code (element, 1)} instead.
   *
   * @param element the element to add one occurrence of; may be null only if explicitly allowed by
   *     the implementation

  }

  public void testForMapWithoutDefault() {
    Map<String, @Nullable Integer> map = new HashMap<>();
    map.put("One", 1);
    map.put("Three", 3);
    map.put("Null", null);
    Function<String, @Nullable Integer> function = Functions.forMap(map);

    assertEquals(1, function.apply("One").intValue());
    assertEquals(3, function.apply("Three").intValue());
    assertThat(function.apply("Null")).isNull();

      BigInteger plusHalfSquared = result.pow(2).add(result).shiftLeft(2).add(ONE);
      BigInteger x4 = x.shiftLeft(2);
      // sqrt(x) < result + 0.5, so 4 * x < (result + 0.5)^2 * 4
      // (result + 0.5)^2 * 4 = (result^2 + result)*4 + 1
      assertThat(plusHalfSquared).isGreaterThan(x4);
      BigInteger minusHalfSquared = result.pow(2).subtract(result).shiftLeft(2).add(ONE);
      // sqrt(x) > result - 0.5, so 4 * x > (result - 0.5)^2 * 4

  public void testEmptySetLast() {
    assertThrows(NoSuchElementException.class, () -> sortedSet.last());
  }

  @CollectionSize.Require(ONE)
  public void testSingletonSetFirst() {
    assertEquals(a, sortedSet.first());
  }

  @CollectionSize.Require(ONE)
  public void testSingletonSetLast() {
    assertEquals(a, sortedSet.last());
  }

  @CollectionSize.Require(SEVERAL)
  public void testFirst() {

 * `::1` will reach the IPv6 server.
 *
 * By orchestrating two different servers with the same port but different IP addresses, we can
 * test what OkHttp does when both are reachable, or if only one is reachable.
 *
 * This test only runs on host machines that have both IPv4 and IPv6 addresses for localhost.
 */
@Timeout(30)
class FastFallbackTest {
  @RegisterExtension
  val clientTestRule = OkHttpClientTestRule()

       * errorMessageTemplate parameters: It is unlikely that callers intend for their string
       * template to be null (though we do handle that case gracefully at runtime). I've left this
       * one as it is because one of our users has defined a wrapper API around Preconditions,
       * declaring a checkState method that accepts a possibly null template. So we'd need to update
       * that user first.
       */

  /** Test an empty collection. */
  ZERO(0),
  /** Test a one-element collection. */
  ONE(1),
  /** Test a three-element collection. */
  SEVERAL(3),
  /*
   * TODO: add VERY_LARGE, noting that we currently assume that the fourth
   * sample element is not in any collection
   */

  ANY(ZERO, ONE, SEVERAL);

  private final Set<Feature<? super Collection>> implied;

  /** Test an empty collection. */
  ZERO(0),
  /** Test a one-element collection. */
  ONE(1),
  /** Test a three-element collection. */
  SEVERAL(3),
  /*
   * TODO: add VERY_LARGE, noting that we currently assume that the fourth
   * sample element is not in any collection
   */

  ANY(ZERO, ONE, SEVERAL);

  private final Set<Feature<? super Collection>> implied;

    worked everywhere that I know of except for one place: when running the GWT
    util.concurrent tests under Guava.

    The problem is that GWT responds poorly to two .gwt.xml files in the same
    Java package; see
    https://groups.google.com/g/google-web-toolkit-contributors/c/CqYH59Dt_rQ/m/uVGW1QdUsXUJ
    for details.

    The summary is that it ignores one file in favor of the other.

       *   setFuture called on it: Neither of those can happen until we've finished processing all
       *   the completed inputs. And we're still processing at least one input, the one that
       *   triggered handleException.)
       *
       * TODO(cpovirk): Think about whether we could/should use Verify to check the return value of
       * addCausalChain.
       */