### Question:
DefaultMetricsReader implements MetricsReader { private MetricValue readHeapUtilization() { Map<String, Metric> metrics = memoryMetricSet.getMetrics(); MetricValue value = null; if (metrics.containsKey(MEMORY_HEAP_UTIL_KEY)) { value = MetricValue.percent( (Double) ((Gauge) metrics.get(MEMORY_HEAP_UTIL_KEY)).getValue()); } return value; } DefaultMetricsReader(); @Override List<MetricName> readableNames(); @Override MetricValue readValue(MetricName name);  }### Answer:
@Test public void testReadHeapUtilization() { System.out.println("testReadHeapUtilization"); DefaultMetricsReader reader = new DefaultMetricsReader(); MetricValue value = reader.readValue(MetricName.HEAP_UTILIZATION); assertThat(value, notNullValue()); assertThat(value.getUnit(), equalTo(MetricUnit.PERCENT)); assertThat(value.getValue(), greaterThanOrEqualTo(0.0)); assertThat(value.getValue(), lessThanOrEqualTo(100.0)); }