fix(test): fix broken code

tests/test_onnx_image_encoder.py

@@ -8,7 +8,6 @@
 from gnes.preprocessor.image.sliding_window import VanillaSlidingPreprocessor
 from gnes.proto import gnes_pb2, blob2array
 
-
 def img_process_for_test(dirname):
     zipfile_ = zipfile.ZipFile(os.path.join(dirname, 'imgs/test.zip'))
     all_bytes = [zipfile_.open(v).read() for v in zipfile_.namelist()]
@@ -28,8 +27,8 @@ def img_process_for_test(dirname):
         for img in test_img_copy:
             preprocessor.apply(img)
         test_img_all_preprocessor.append([blob2array(chunk.blob)
-                                          for img in 
-
+                                          for img in test_img_copy for chunk in img.chunks])
+    return test_img_all_preprocessor
 
 class TestONNXImageEncoder(unittest.TestCase):