assertCannotSet(future);
    assertPending(future);
  }

  private static void assertPending(AbstractFuture<?> future) {
    assertThat(future.isDone()).isFalse();
    assertThat(future.isCancelled()).isFalse();

    CountingRunnable listener = new CountingRunnable();
    future.addListener(listener, directExecutor());
    listener.assertNotRun();

    verifyGetOnPendingFuture(future);

            future.set(null);
          }
        };
    unused = null; // Hint to the JIT that unused is unreachable
    GcFinalization.awaitDone(future);
    assertTrue(future.isDone());
    assertFalse(future.isCancelled());
  }

  public void testAwaitDone_future_cancel() {
    SettableFuture<@Nullable Void> future = SettableFuture.create();
    Object unused =
        new Object() {

            future.set(null);
          }
        };
    unused = null; // Hint to the JIT that unused is unreachable
    GcFinalization.awaitDone(future);
    assertTrue(future.isDone());
    assertFalse(future.isCancelled());
  }

  public void testAwaitDone_future_cancel() {
    SettableFuture<@Nullable Void> future = SettableFuture.create();
    Object unused =
        new Object() {

      results.add(serializer.submit(Callables.returning(null), directExecutor()));
    }

    manualExecutorTask[0].run();

    for (Future<?> result : results) {
      if (!result.isCancelled()) {
        result.get(10, SECONDS);
      }
      // TODO(cpovirk): Verify that the cancelled futures are exactly ones that we expect.
    }

    assertThat(logHandler.getStoredLogRecords()).isEmpty();
  }

      results.add(serializer.submit(Callables.returning(null), directExecutor()));
    }

    manualExecutorTask[0].run();

    for (Future<?> result : results) {
      if (!result.isCancelled()) {
        result.get(10, SECONDS);
      }
      // TODO(cpovirk): Verify that the cancelled futures are exactly ones that we expect.
    }

    assertThat(logHandler.getStoredLogRecords()).isEmpty();
  }

    NullService service = new NullService();
    service.startAsync().awaitRunning();
    assertFalse(future.isDone());
    service.stopAsync().awaitTerminated();
    assertTrue(future.isCancelled());
  }

  private class NullService extends AbstractScheduledService {
    @Override
    protected void runOneIteration() throws Exception {}

    @Override
    protected Scheduler scheduler() {

    NullService service = new NullService();
    service.startAsync().awaitRunning();
    assertFalse(future.isDone());
    service.stopAsync().awaitTerminated();
    assertTrue(future.isCancelled());
  }

  private class NullService extends AbstractScheduledService {
    @Override
    protected void runOneIteration() throws Exception {}

    @Override
    protected Scheduler scheduler() {

            // future that eventually came from immediateVoidFuture(), this doesn't leak throwables
            // or completion values.
            newFuture.setFuture(oldFuture);
          } else if (outputFuture.isCancelled() && taskExecutor.trySetCancelled()) {
            // If this CAS succeeds, we know that the provided callable will never be invoked,
            // so when oldFuture completes it is safe to allow the next submitted task to