`No, indeed,' said Alice.  `What sort of a dance is it?'

  `Why,' said the Gryphon, `you first form into a line along the sea-shore--'

  `Two lines!' cried the Mock Turtle.  `Seals, turtles, salmon, and so on;
then, when you've cleared all the jelly-fish out of the way--'

  `THAT generally takes some time,' interrupted the Gryphon.

  `--you advance twice--'

  }

  /** Constructs a listenable future with a value available after the latch has counted down. */
  protected abstract <V> ListenableFuture<V> createListenableFuture(
      V value, @Nullable Exception except, CountDownLatch waitOn);

  /** Tests that the {@link Future#get()} method blocks until a value is available. */
  public void testGetBlocksUntilValueAvailable() throws Throwable {

    assertFalse(future.isDone());

  }

  /** Constructs a listenable future with a value available after the latch has counted down. */
  protected abstract <V> ListenableFuture<V> createListenableFuture(
      V value, @Nullable Exception except, CountDownLatch waitOn);

  /** Tests that the {@link Future#get()} method blocks until a value is available. */
  public void testGetBlocksUntilValueAvailable() throws Throwable {

    assertFalse(future.isDone());

  `No, indeed,' said Alice.  `What sort of a dance is it?'

  `Why,' said the Gryphon, `you first form into a line along the sea-shore--'

  `Two lines!' cried the Mock Turtle.  `Seals, turtles, salmon, and so on;
then, when you've cleared all the jelly-fish out of the way--'

  `THAT generally takes some time,' interrupted the Gryphon.

  `--you advance twice--'