code: @Test public void testMetrics() throws Exception {
    InMemoryMetricRepository repository=new InMemoryMetricRepository();
    repository.set(new Metric<Double>("a",0.5,new Date()));
    VanillaPublicMetrics publicMetrics=new VanillaPublicMetrics(repository);
    Map<String,Metric<?>> results=new HashMap<String,Metric<?>>();
    for (  Metric<?> metric : publicMetrics.metrics()) {
      results.put(metric.getName(),metric);
    }
    assertTrue(results.containsKey("mem"));
    assertTrue(results.containsKey("mem.free"));
    assertThat(results.get("a").getValue().doubleValue(),equalTo(0.5));
  }
  