// Wait for the listeners to be called, don't rely on the same-thread exec.
    listenerLatch.await(5, TimeUnit.SECONDS);
    assertTrue(task.isDone());
    assertTrue(task.isCancelled());

    // Make sure we didn't run anything.
    assertEquals(1, runLatch.getCount());
  }

  public void testListenerCalledOnCancelFromRunning() throws Exception {
    exec.execute(task);
    runLatch.await();

@GwtCompatible(emulated = true)
@ElementTypesAreNonnullByDefault
abstract class CollectionFuture<V extends @Nullable Object, C extends @Nullable Object>
    extends AggregateFuture<V, C> {
  /*
   * We access this field racily but safely. For discussion of a similar situation, see the comments
   * on the fields of TimeoutFuture. This field is slightly different from the fields discussed

  private MinimalIterable(Iterator<E> iterator) {
    this.iterator = iterator;
  }

  @Override
  public Iterator<E> iterator() {
    if (iterator == null) {
      // TODO: throw something else? Do we worry that people's code and tests
      // might be relying on this particular type of exception?
      throw new IllegalStateException();
    }
    try {
      return iterator;
    } finally {
      iterator = null;

    return new SingletonImmutableSet<>(element);
  }

  /*
   * TODO: b/315526394 - Skip the Builder entirely for the of(...) methods, since we don't need to
   * worry that we might trigger the fallback to the JDK-backed implementation? (The varargs one
   * _could_, so we could keep it as it is. Or we could convince ourselves that hash flooding is
   * unlikely in practice there, too.)
   */

  /**

          public void checkAccess(Thread t) {
            throw new SecurityException();
          }

          @Override
          public void checkPermission(Permission perm) {
            // Do nothing so we can clear the security manager at the end
          }
        });
    try {
      final String oldName = Thread.currentThread().getName();
      Supplier<String> newName = Suppliers.ofInstance("MyCrazyThreadName");

      <groupId>com.google.truth</groupId>
      <artifactId>truth</artifactId>
      <version>${truth.version}</version>
      <scope>test</scope>
      <exclusions>
        <exclusion>
          <!-- use the guava we're building. -->
          <groupId>com.google.guava</groupId>
          <artifactId>guava</artifactId>
        </exclusion>
      </exclusions>
    </dependency>
  </dependencies>
  <build>
    <plugins>

     * StackOverflowError: We can't reliably call setException(error).
     *
     * - Any kind of Error from a listener. Even if we could distinguish that case (by exposing some
     * extra state from AbstractFuture), our options are limited: A call to setException() would be
     * a no-op. We could log, but if that's what we really want, we should modify

   */
  public static void checkState(
      boolean expression,
      /*
       * TODO(cpovirk): Consider removing @CheckForNull here, as we've done with the other methods'
       * 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,

        it just seem like a sensible behavior for the feature to have?


        Before we make significant changes to existing features in Guava, we really want to be sure
        that it's for a use case that actually comes up in the real world. We want to hear the
        real-world use case so the community can discuss and debate whether this feature is actually

    try {
      Hashing.hmacMd5(badKey);
      fail();
    } catch (IllegalArgumentException expected) {
    } catch (NullPointerException toleratedOnAndroid) {
      // TODO(cpovirk): In an ideal world, we'd check here that we're running on Android.
    }
  }

  public void testEmptyInputs() throws Exception {
    String knownOutput = "8cbf764cbe2e4623d99a41354adfd390";

    Mac mac = Mac.getInstance("HmacMD5");