private static class TestedFuture<V> extends AbstractFuture<V> {
    private static <V> TestedFuture<V> create() {
      return new TestedFuture<V>();
    }
  }

  private static final class CountingRunnable implements Runnable {
    int count;

    @Override
    public void run() {
      count++;
    }

    void assertNotRun() {
      assertEquals(0, count);
    }