@Test
public void testStopTiming() {

    Summary.Timer timer = mock(Summary.Timer.class);
    PrometheusMetric metric = new PrometheusMetric(null, null, null, "", false, false, false, false, false);
    metric.stopTiming(timer);
    // assertions
    verify(timer, times(1)).observeDuration();
    // different signature
    metric.stopTiming(timer, "request_domain", "principal_domain");
    // assertions
    verify(timer, times(2)).observeDuration();
}