code: @Test public void incrementGroup(){
    this.repository.increment("foo",new Delta<Number>("foo.bar",1));
    this.repository.increment("foo",new Delta<Number>("foo.bar",2));
    this.repository.increment("foo",new Delta<Number>("foo.spam",1));
    Set<String> names=new HashSet<String>();
    for (  Metric<?> metric : this.repository.findAll("foo")) {
      names.add(metric.getName());
    }
    assertEquals(2,names.size());
    assertTrue(names.contains("foo.bar"));
    assertEquals(3L,this.repository.findOne("foo.bar").getValue());
  }
  