@Test
public void testEmptyStreamProducesZeros() {

    HystrixCommandGroupKey groupKey = HystrixCommandGroupKey.Factory.asKey("ThreadPool-Concurrency-A");
    HystrixThreadPoolKey threadPoolKey = HystrixThreadPoolKey.Factory.asKey("ThreadPool-Concurrency-A");
    HystrixCommandKey key = HystrixCommandKey.Factory.asKey("RollingConcurrency-A");
    stream = RollingThreadPoolMaxConcurrencyStream.getInstance(threadPoolKey, 10, 100);
    stream.startCachingStreamValuesIfUnstarted();
    final CountDownLatch latch = new CountDownLatch(1);
    stream.observe().take(10).subscribe(getSubscriber(latch));
    //no writes
    try {
        assertTrue(latch.await(10000, TimeUnit.MILLISECONDS));
    } catch (InterruptedException ex) {
        fail("Interrupted ex");
    }
    assertEquals(0, stream.getLatestRollingMax());
}