public void report() {
        synchronized (this) {
            report(registry.getGauges(filter),
                    registry.getCounters(filter),
                    registry.getHistograms(filter),
                    registry.getMeters(filter),
                    registry.getTimers(filter));
        }
    }
@Test
    public void pollsPeriodically() throws Exception {
        Thread.sleep(500);
        verify(reporter, times(2)).report(
                map("gauge", gauge),
                map("counter", counter),
                map("histogram", histogram),
                map("meter", meter),
                map("timer", timer)
        );
    }