BlobsServiceImpl implements BlobsService { @Override public List<Entity> extractEntitiesFromBlob(BlobKey blobKey) { JsonReader jsonReader = jsonBlobReaderFactory.create(blobKey); return gson.fromJson(jsonReader, new TypeToken<List<Entity>>() { }.getType()); } @Inject  BlobsServiceImpl(
            BlobInfoFactory blobInfoFactory,
            JsonBlobReaderFactory jsonBlobReaderFactory,
            Gson gson); @Override Iterator<BlobInfo> getAllBlobInfos(); @Override List<Entity> extractEntitiesFromBlob(BlobKey blobKey);  }
@Test public void extractEntitiesFromBlob() throws Exception { BlobKey blobKey = createCarBlob(); List<Entity> entities = blobsService.extractEntitiesFromBlob(blobKey); assertEquals(1, entities.size()); }