@Test
public void oneCellFailing() {

    cellOne.getServiceRegistry().addService(new CellWithHealthStatus(ok("one")));
    cellTwo.getServiceRegistry().addService(new CellWithHealthStatus(failing("two")));
    AssertableSubscriber<HealthCheckResponse> subscriber = service.check(HealthCheckRequest.newBuilder().build()).test();
    subscriber.awaitTerminalEvent(10, TimeUnit.SECONDS);
    subscriber.assertNoErrors();
    subscriber.assertValueCount(1);
    HealthCheckResponse response = subscriber.getOnNextEvents().get(0);
    assertThat(response.getStatus()).isEqualTo(NOT_SERVING);
    assertThat(response.getDetailsCount()).isEqualTo(2);
    assertThat(response.getDetails(0).hasDetails()).isTrue();
    assertThat(response.getDetails(1).hasDetails()).isTrue();
    Set<String> cellsSeen = response.getDetailsList().stream()
            .map(s -> s.getDetails().getCell())
            .collect(Collectors.toSet());
    assertThat(cellsSeen).contains("one", "two");
}