assertTrue("All callbacks should complete", latch.await(10, TimeUnit.SECONDS));
        assertEquals("All 3 callbacks should be invoked", 3, callbackCount.get());
    }

    @Test
    public void test_multipleErrorCallbacks_allInvoked() throws Exception {
        final Deferred<SuggestResponse> deferred = new Deferred<>();
        final AtomicInteger callbackCount = new AtomicInteger(0);