/**
   * Performs a {@linkplain java.lang.invoke.VarHandle#compareAndSet compare-and-set} operation on
   * {@link #valueField} of {@code future}.
   */
  static boolean casValue(AbstractFutureState<?> future, @Nullable Object expect, Object update) {
    return ATOMIC_HELPER.casValue(future, expect, update);
  }

  /** Returns the value of the future, using a volatile read. */
  final @Nullable Object value() {
    return valueField;
  }

      return true;
    }
    return false;
  }

  final @Nullable Listener gasListeners(Listener update) {
    Listener old = listeners;
    listeners = update;
    return old;
  }

  static boolean casValue(AbstractFutureState<?> future, @Nullable Object expect, Object update) {
    if (future.value == expect) {
      future.value = update;
      return true;
    }
    return false;
  }

      if (owner.value() != this) {
        // nothing to do, we must have been cancelled, don't bother inspecting the future.
        return;
      }
      Object valueToSet = getFutureValue(future);
      if (casValue(owner, this, valueToSet)) {
        complete(
            owner,
            /*
             * Interruption doesn't propagate through a DelegatingToFuture chain (see

     * anything that might slow down execution on such a hot path. Given that the methods are only
     * package-private, I feel OK with just not testing them for NPE.
     *
     * Note that testing casValue is particularly dangerous because it uses Unsafe under some
     * versions of Java, and apparently Unsafe can cause SIGSEGV instead of NPE—almost as if it's
     * not safe.
     */
    concat(

     * anything that might slow down execution on such a hot path. Given that the methods are only
     * package-private, I feel OK with just not testing them for NPE.
     *
     * Note that testing casValue is particularly dangerous because it uses Unsafe under some
     * versions of Java, and apparently Unsafe can cause SIGSEGV instead of NPE—almost as if it's
     * not safe.
     */
    concat(

    HONDA,
    POODLE,
  }

  public void testGetIfPresent() {
    assertThat(Enums.getIfPresent(TestEnum.class, "CHEETO")).hasValue(TestEnum.CHEETO);
    assertThat(Enums.getIfPresent(TestEnum.class, "HONDA")).hasValue(TestEnum.HONDA);
    assertThat(Enums.getIfPresent(TestEnum.class, "POODLE")).hasValue(TestEnum.POODLE);

    assertThat(Enums.getIfPresent(TestEnum.class, "CHEETO")).isPresent();

    HONDA,
    POODLE,
  }

  public void testGetIfPresent() {
    assertThat(Enums.getIfPresent(TestEnum.class, "CHEETO")).hasValue(TestEnum.CHEETO);
    assertThat(Enums.getIfPresent(TestEnum.class, "HONDA")).hasValue(TestEnum.HONDA);
    assertThat(Enums.getIfPresent(TestEnum.class, "POODLE")).hasValue(TestEnum.POODLE);

    assertThat(Enums.getIfPresent(TestEnum.class, "CHEETO")).isPresent();

    assertThat(iterable.firstMatch(equalTo("cool"))).hasValue("cool");
    assertThat(iterable.firstMatch(equalTo("pants"))).hasValue("pants");
    assertThat(iterable.firstMatch(Predicates.alwaysFalse())).isAbsent();
    assertThat(iterable.firstMatch(Predicates.alwaysTrue())).hasValue("cool");
  }

  private static final class IntegerValueOfFunction implements Function<String, Integer> {

    assertThat(MediaType.parse("text/plain; charset =utf-8").charset()).hasValue(UTF_8);
    assertThat(MediaType.parse("text/plain; charset= utf-8").charset()).hasValue(UTF_8);
    assertThat(MediaType.parse("text/plain; charset = utf-8").charset()).hasValue(UTF_8);
    assertThat(MediaType.parse("text/plain;charset =utf-8").charset()).hasValue(UTF_8);
  }

  public void testGetCharset() {

    graph.putEdgeValue(1, 2, "A");
    assertThat(graph.edgeValue(EndpointPair.unordered(1, 2))).hasValue("A");
  }

  @Test
  public void edgeValue_undirected_backwards() {
    graph = ValueGraphBuilder.undirected().build();
    graph.putEdgeValue(1, 2, "A");
    assertThat(graph.edgeValue(EndpointPair.unordered(2, 1))).hasValue("A");
  }

  @Test
  public void edgeValue_undirected_mismatch() {