CategoriesPersistenceService extends PersistenceService<Categories> { @Override Categories defaultInstance() { try (InputStream stream = CategoriesPersistenceService.class.getResourceAsStream("default-categories.json")) { return read(stream); } catch (IOException e) { throw Throwables.propagate(e); } } @Inject  CategoriesPersistenceService(PersistenceGsonProvider gsonProvider, DataDirectoryLocator dataDirectoryLocator);   }
@Test public void defaultInstance() { Categories categories = service.defaultInstance(); assertDefaultCategories(categories); }