### Question:
ArtemisRegistryHttpClient extends ArtemisHttpClient { public void unregister(final Set<Instance> instances) { try { Preconditions.checkArgument(!CollectionUtils.isEmpty(instances), "instances"); final UnregisterRequest request = new UnregisterRequest(Lists.newArrayList(instances)); final UnregisterResponse response = this.request(RestPaths.REGISTRY_UNREGISTER_FULL_PATH, request, UnregisterResponse.class); if (ResponseStatusUtil.isFail(response.getResponseStatus())) { _logger.error("unregister instances failed. Response:" + JacksonJsonSerializer.INSTANCE.serialize(response)); } else if (ResponseStatusUtil.isPartialFail(response.getResponseStatus())) { _logger.warn("unregister instances patial failed. Response:" + JacksonJsonSerializer.INSTANCE.serialize(response)); } logEvent(response.getResponseStatus(), "registry", "unregister"); } catch (final Throwable e) { _logger.warn("unregister instances failed", e); logEvent("registry", "unregister"); } } ArtemisRegistryHttpClient(final ArtemisClientConfig config); void register(final Set<Instance> instances); void unregister(final Set<Instance> instances);  }### Answer:
@Test public void testUnregister() throws Exception { client.unregister(Instances.newInstances(3)); }