public function callsCancelOnPromisesEnqueuedBeforeStart()
{
$d1 = $this->getCancellableDeferred();
$d2 = $this->getCancellableDeferred();
$cancellationQueue = new CancellationQueue();
$cancellationQueue->enqueue($d1->promise());
$cancellationQueue->enqueue($d2->promise());
$cancellationQueue();
}