cancelling a scheduled future while it is running has no effect

CancellingAScheduledFutureWhileItIsRunningHasNoEffect.java

    @Test
    public void cancellingAScheduledFutureWhileItIsRunningHasNoEffect() {
        DeterministicScheduler deterministicScheduler = new DeterministicScheduler();
        SchedulerContainer schedulerContainer = new SchedulerContainer(deterministicScheduler);
        schedulerContainer.scheduleSelfCancellingTask();
        deterministicScheduler.tick(2,TimeUnit.SECONDS);
        assertThat(schedulerContainer.runCount(), is(1));
    }
    public static class SchedulerContainer {

        private final ScheduledExecutorService scheduler;
        private ScheduledFuture<?> scheduledFuture;
        private final AtomicInteger counter = new AtomicInteger();
        public SchedulerContainer(ScheduledExecutorService scheduler) {
            this.scheduler = scheduler;
        }
        public void scheduleSelfCancellingTask(){
            scheduledFuture = scheduler.scheduleAtFixedRate(
                    new CancellingRunnable(), 1, 1, TimeUnit.SECONDS);
        }
        public int runCount(){
            return counter.get();
        }
        private class CancellingRunnable implements Runnable{
            @Override
            public void run() {
                scheduledFuture.cancel(true);
                counter.incrementAndGet();
            }
        }
    }