@Test
public void testUseLogObserver() {

    LogObserver logObserver = new LogObserver(new StringLog());
    Id id = new DefaultRegistry().createId("aa");
    LookoutMeasurement measurement = new LookoutMeasurement(new Date(), id);
    measurement.addTag("k", "v");
    measurement.put("v", 2);
    List<LookoutMeasurement> measurements = new ArrayList<LookoutMeasurement>();
    measurements.add(measurement);
    logObserver.update(measurements, null);
    Assert.assertTrue(str.contains("\"tags\":{\"k\":\"v\"}"));
}