@Override
    public synchronized void failed(State from, Throwable failure) {
      assertEquals(from, Iterables.getLast(stateHistory));
      stateHistory.add(State.FAILED);
      assertEquals(State.FAILED, service.state());
      assertEquals(failure, service.failureCause());
      if (from == State.STARTING) {
        try {
          service.awaitRunning();
          fail();
        } catch (IllegalStateException e) {

  static final Exception CHECKED_EXCEPTION = new Exception("mymessage");
  static final Future<String> FAILED_FUTURE_CHECKED_EXCEPTION =
      immediateFailedFuture(CHECKED_EXCEPTION);
  static final RuntimeException UNCHECKED_EXCEPTION = new RuntimeException("mymessage");
  static final Future<String> FAILED_FUTURE_UNCHECKED_EXCEPTION =
      immediateFailedFuture(UNCHECKED_EXCEPTION);

      equalsTester.addEqualityGroup((Object) null);
      fail("Should fail on null reference");
    } catch (NullPointerException e) {
    }
  }

  /** Test equalObjects after adding multiple instances at once with a null */
  public void testAddTwoEqualObjectsAtOnceWithNull() {
    try {
      equalsTester.addEqualityGroup(reference, equalObject1, null);
      fail("Should fail on null equal object");
    } catch (NullPointerException e) {

 *     Guava 27.0
 */
public final class InternalFutures {
  /**
   * Usually returns {@code null} but, if the given {@code Future} has failed, may <i>optionally</i>
   * return the cause of the failure. "Failure" means specifically "completed with an exception"; it
   * does not include "was cancelled." To be explicit: If this method returns a non-null value,
   * then:

import static com.google.common.util.concurrent.FuturesGetCheckedInputs.FAILED_FUTURE_CHECKED_EXCEPTION;
import static com.google.common.util.concurrent.FuturesGetCheckedInputs.FAILED_FUTURE_ERROR;
import static com.google.common.util.concurrent.FuturesGetCheckedInputs.FAILED_FUTURE_OTHER_THROWABLE;
import static com.google.common.util.concurrent.FuturesGetCheckedInputs.FAILED_FUTURE_UNCHECKED_EXCEPTION;

    assertLessThan(STARTING, STOPPING);
    assertLessThan(STARTING, FAILED);

    assertLessThan(RUNNING, STOPPING);
    assertLessThan(RUNNING, FAILED);

    assertLessThan(STOPPING, FAILED);
    assertLessThan(STOPPING, TERMINATED);
  }

  private static <T extends Comparable<? super T>> void assertLessThan(T a, T b) {
    if (a.compareTo(b) >= 0) {
      fail(String.format(Locale.ROOT, "Expected %s to be less than %s", a, b));
    }

       *   cause if this Future has failed.
       *
       * - And this future *has* failed: This method is called only from handleException (through
       *   getOrInitSeenExceptions). handleException tried to call setException and failed, so
       *   either this Future was cancelled (which we ruled out with the isCancelled check above),
       *   or it had already failed. (It couldn't have completed *successfully* or even had

      new ForwardingWrapperTester()
          .includingEquals()
          .testForwarding(Equals.class, NoDelegateToEquals.WRAPPER);
    } catch (AssertionFailedError expected) {
      return;
    }
    fail("Should have failed");
  }

  /** An interface for the 2 ways that a chaining call might be defined. */
  private interface ChainingCalls {
    // A method that is defined to 'return this'
    @CanIgnoreReturnValue

    assertFalse(listener.healthyCalled);
  }

  /**
   * This covers a bug where if a listener was installed that would stop the manager if any service
   * fails and something failed during startup before service.start was called on all the services,
   * then awaitStopped would deadlock due to an IllegalStateException that was thrown when trying to
   * stop the timer(!).
   */

    READY,
    NOT_READY,
    DONE,
    FAILED,
  }

  @CheckForNull private T next;

  @CheckForNull
  protected abstract T computeNext();

  @CanIgnoreReturnValue
  @CheckForNull
  protected final T endOfData() {
    state = State.DONE;
    return null;
  }

  @Override
  public final boolean hasNext() {
    checkState(state != State.FAILED);
    switch (state) {
      case DONE: