@Test
public void reportsGaugeValues() throws Exception {

    final Gauge<Integer> gauge = () -> 1;
    reporter.report(map("gauge", gauge),
            map(),
            map(),
            map(),
            map());
    assertThat(fileContents("gauge.csv"))
            .isEqualTo(csv(
                    "t,value",
                    "19910191,1"
            ));
}