@Test
  public void link_linkRelated() {
    String relatedLink = UUID.randomUUID().toString();
    MeterReading meterReading = EspiFactory.newMeterReading();
    meterReading.setUpLink(new LinkType(LinkType.UP, relatedLink));
    resourceService.persist(meterReading);
    UsagePoint usagePoint = factory.createUsagePoint();
    usagePoint.getRelatedLinks().add(new LinkType(LinkType.RELATED, relatedLink));
    resourceService.persist(usagePoint);

    assertThat(meterReading.getUsagePoint(), is(nullValue()));

    linker.link(usagePoint);

    assertThat(meterReading.getUsagePoint(), equalTo(usagePoint));
  }