@Test
  public void testUpgrade() throws Exception {
    initializeOneAgent();

    UpgradeVersions upgradeVersions = new UpgradeVersions("2.0", "2.0");
    Request request =
        Request.Builder.preparePost()
            .setUri(
                coordinatorUriBuilder()
                    .appendPath("/v1/slot/assignment")
                    .addParameter("host", "apple*")
                    .build())
            .setHeader(CONTENT_TYPE, APPLICATION_JSON)
            .setBodyGenerator(jsonBodyGenerator(upgradeVersionsCodec, upgradeVersions))
            .build();
    List<SlotStatusRepresentation> actual =
        httpClient.execute(
            request, createJsonResponseHandler(slotStatusesCodec, Status.OK.getStatusCode()));

    AgentStatus agentStatus = coordinator.getAgentByAgentId(agentId);
    SlotStatus apple1Status = agentStatus.getSlotStatus(apple1SotId);
    SlotStatus apple2Status = agentStatus.getSlotStatus(apple2SlotId);
    SlotStatus bananaStatus = agentStatus.getSlotStatus(bananaSlotId);

    List<SlotStatusRepresentation> expected =
        ImmutableList.of(
            slotStatusRepresentationFactory.create(apple1Status),
            slotStatusRepresentationFactory.create(apple2Status));

    assertEqualsNoOrder(actual, expected);

    assertEquals(apple1Status.getState(), STOPPED);
    assertEquals(apple2Status.getState(), STOPPED);
    assertEquals(bananaStatus.getState(), STOPPED);

    assertEquals(
        apple1Status.getAssignment(),
        upgradeVersions.upgradeAssignment(MOCK_REPO, APPLE_ASSIGNMENT));
    assertEquals(
        apple2Status.getAssignment(),
        upgradeVersions.upgradeAssignment(MOCK_REPO, APPLE_ASSIGNMENT));
    assertEquals(bananaStatus.getAssignment(), BANANA_ASSIGNMENT);
  }
  private List<ServiceDescriptor> getServiceInventory(SlotStatus slotStatus) {
    Assignment assignment = slotStatus.getAssignment();
    if (assignment == null) {
      return null;
    }

    String config = assignment.getConfig();

    File cacheFile = getCacheFile(config);
    if (cacheFile.canRead()) {
      try {
        String json = CharStreams.toString(Files.newReaderSupplier(cacheFile, Charsets.UTF_8));
        List<ServiceDescriptor> descriptors = descriptorsJsonCodec.fromJson(json);
        invalidServiceInventory.remove(config);
        return descriptors;
      } catch (Exception ignored) {
        // delete the bad cache file
        cacheFile.delete();
      }
    }

    InputSupplier<? extends InputStream> configFile =
        ConfigUtils.newConfigEntrySupplier(repository, config, "airship-service-inventory.json");
    if (configFile == null) {
      return null;
    }

    try {
      String json;
      try {
        json = CharStreams.toString(CharStreams.newReaderSupplier(configFile, Charsets.UTF_8));
      } catch (FileNotFoundException e) {
        // no service inventory in the config, so replace with json null so caching works
        json = "null";
      }
      invalidServiceInventory.remove(config);

      // cache json
      cacheFile.getParentFile().mkdirs();
      Files.write(json, cacheFile, Charsets.UTF_8);

      List<ServiceDescriptor> descriptors = descriptorsJsonCodec.fromJson(json);
      return descriptors;
    } catch (Exception e) {
      if (invalidServiceInventory.add(config)) {
        log.error(e, "Unable to read service inventory for %s" + config);
      }
    }
    return null;
  }
  private void assertOkResponse(Response response, SlotLifecycleState state, UUID... slotIds) {
    assertEquals(response.getStatus(), Response.Status.OK.getStatusCode());

    AgentStatus agentStatus = coordinator.getAgentByAgentId(agentId);
    Builder<SlotStatusRepresentation> builder = ImmutableList.builder();
    for (UUID slotId : slotIds) {
      SlotStatus slotStatus = agentStatus.getSlotStatus(slotId);
      builder.add(
          SlotStatusRepresentation.from(slotStatus.changeState(state), prefixSize, MOCK_REPO));
      assertEquals(slotStatus.getAssignment(), APPLE_ASSIGNMENT);
    }
    assertEqualsNoOrder((Collection<?>) response.getEntity(), builder.build());
    assertNull(
        response
            .getMetadata()
            .get("Content-Type")); // content type is set by jersey based on @Produces
  }