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);

 *     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:

    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));
    }

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;

        assertThrows(RuntimeException.class, () -> service.startAsync().awaitRunning());
    assertThat(e).hasCauseThat().isSameInstanceAs(exception);
    assertEquals(Service.State.FAILED, service.state());
  }

  public void testFunctionalStop_failed() {
    final Exception exception = new Exception("deliberate");
    AbstractIdleService service =
        new DefaultService() {
          @Override

    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:

    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:

        throw new RuntimeException(e);
      } catch (InvocationTargetException e) {
        throw Throwables.propagate(e.getCause());
      }
      assertEquals("Failed to forward to " + method, 1, called.get());
    }

    @Override
    public String toString() {
      return "dummy " + interfaceType.getSimpleName();
    }
  }

        throw new RuntimeException(e);
      } catch (InvocationTargetException e) {
        throw Throwables.propagate(e.getCause());
      }
      assertEquals("Failed to forward to " + method, 1, called.get());
    }

    @Override
    public String toString() {
      return "dummy " + interfaceType.getSimpleName();
    }
  }

    try {
      unicodeEscaper.escape("\uD800x\uDC00");
      fail("should have failed for bad Unicode input");
    } catch (IllegalArgumentException e) {
      // pass
    }
    assertEquals("<lo><hi>", charEscaper.escape("\uDC00\uD800"));
    try {
      unicodeEscaper.escape("\uDC00\uD800");
      fail("should have failed for bad Unicode input");
    } catch (IllegalArgumentException e) {
      // pass