### Question:
DefaultMetricsReader implements MetricsReader { private MetricValue readQueueLength() { MetricValue value = null; Counter queueLength = metricRegistry .counter(MetricName.QUEUE_LENGTH.getName()); if (queueLength != null) { value = MetricValue.tuples(Long.valueOf( queueLength.getCount()).intValue()); } return value; } DefaultMetricsReader(); @Override List<MetricName> readableNames(); @Override MetricValue readValue(MetricName name);  }### Answer:
@Test public void testReadQueueLength() { System.out.println("testReadQueueLength"); DefaultMetricsReader reader = new DefaultMetricsReader(); MetricValue value = reader.readValue(MetricName.QUEUE_LENGTH); assertThat(value, notNullValue()); assertThat(value.getUnit(), equalTo(MetricUnit.TUPLES)); assertThat(value.getValue(), greaterThanOrEqualTo(0.0)); }