code: @Test public void records404HttpInteractionsAsSingleMetric() throws Exception {
    AnnotationConfigApplicationContext context=new AnnotationConfigApplicationContext(Config.class,MetricFilterAutoConfiguration.class);
    Filter filter=context.getBean(Filter.class);
    MockMvc mvc=MockMvcBuilders.standaloneSetup(new MetricFilterTestController()).addFilter(filter).build();
    mvc.perform(get("/unknownPath/1")).andExpect(status().isNotFound());
    mvc.perform(get("/unknownPath/2")).andExpect(status().isNotFound());
    verify(context.getBean(CounterService.class),times(2)).increment("status.404.unmapped");
    verify(context.getBean(GaugeService.class),times(2)).submit(eq("response.unmapped"),anyDouble());
    context.close();
  }
  