diff --git a/tests/executors/crafters/image/test_crop.py b/tests/executors/crafters/image/test_crop.py
index 05a65ffd64ba5..445699713379a 100644
--- a/tests/executors/crafters/image/test_crop.py
+++ b/tests/executors/crafters/image/test_crop.py
@@ -1,4 +1,5 @@
 import unittest
+
 import numpy as np
 
 from jina.executors.crafters.image.crop import ImageCropper, CenterImageCropper, RandomImageCropper, FiveImageCropper, \
@@ -17,11 +18,11 @@ def test_crop(self):
         crafter = ImageCropper(left, top, width, height)
         crafted_chunk = crafter.craft(img_array, 0, 0)
         np.testing.assert_array_equal(
-            crafted_chunk['blob'], np.asarray(img_array[top:top+height, left:left+width, :]),
+            crafted_chunk['blob'], np.asarray(img_array[top:top + height, left:left + width, :]),
             'img_array: {}\ntest: {}\ncontrol:{}'.format(
                 img_array.shape,
                 crafted_chunk['blob'].shape,
-                np.asarray(img_array[left:left+width, top:top+height, :]).shape))
+                np.asarray(img_array[left:left + width, top:top + height, :]).shape))
 
     def test_center_crop(self):
         img_size = 217
diff --git a/tests/executors/crafters/nlp/split.py b/tests/executors/crafters/nlp/split.py
index 7b75e9b2ef4da..eefed53c29e37 100644
--- a/tests/executors/crafters/nlp/split.py
+++ b/tests/executors/crafters/nlp/split.py
@@ -1,6 +1,7 @@
 import unittest
-from tests import JinaTestCase
+
 from jina.executors.crafters.nlp.split import Sentencizer, JiebaSegmenter
+from tests import JinaTestCase
 
 
 class MyTestCase(JinaTestCase):
@@ -22,5 +23,6 @@ def test_jieba_crafter(self):
         crafted_chunk_list = jieba_crafter.craft(raw_bytes, 0)
         self.assertEqual(len(crafted_chunk_list), 14)
 
+
 if __name__ == '__main__':
     unittest.main()
diff --git a/tests/executors/encoders/image/test_onnx.py b/tests/executors/encoders/image/test_onnx.py
index f27e0757e9f36..48b542cfd3008 100644
--- a/tests/executors/encoders/image/test_onnx.py
+++ b/tests/executors/encoders/image/test_onnx.py
@@ -1,5 +1,4 @@
 import unittest
-import os
 
 from jina.executors.encoders.image.onnx import OnnxImageEncoder
 from . import ImageTestCase
diff --git a/tests/executors/encoders/nlp/__init__.py b/tests/executors/encoders/nlp/__init__.py
index 30583704e5ee3..2a78620ab1c91 100644
--- a/tests/executors/encoders/nlp/__init__.py
+++ b/tests/executors/encoders/nlp/__init__.py
@@ -4,7 +4,6 @@
 import numpy as np
 
 from jina.executors import BaseExecutor
-from jina.executors.encoders.nlp.paddlehub import TextPaddlehubEncoder
 from tests import JinaTestCase
 
 
diff --git a/tests/executors/encoders/numeric/__init__.py b/tests/executors/encoders/numeric/__init__.py
index 81f795d2a4df0..a10e76fb5d6e2 100644
--- a/tests/executors/encoders/numeric/__init__.py
+++ b/tests/executors/encoders/numeric/__init__.py
@@ -1,8 +1,9 @@
-import numpy as np
 import os
 
-from tests import JinaTestCase
+import numpy as np
+
 from jina.executors import BaseExecutor
+from tests import JinaTestCase
 
 
 class NumericTestCase(JinaTestCase):
diff --git a/tests/executors/encoders/numeric/test_pca.py b/tests/executors/encoders/numeric/test_pca.py
index 53d2e37aa45a8..95ca2827518b2 100644
--- a/tests/executors/encoders/numeric/test_pca.py
+++ b/tests/executors/encoders/numeric/test_pca.py
@@ -2,8 +2,8 @@
 
 import numpy as np
 
-from . import NumericTestCase
 from jina.executors.encoders.numeric.pca import IncrementalPCAEncoder
+from . import NumericTestCase
 
 
 class MyTestCase(NumericTestCase):
diff --git a/tests/executors/indexers/keyvalue/test_leveldb.py b/tests/executors/indexers/keyvalue/test_leveldb.py
index eb465d055e35e..b188716285c92 100644
--- a/tests/executors/indexers/keyvalue/test_leveldb.py
+++ b/tests/executors/indexers/keyvalue/test_leveldb.py
@@ -1,10 +1,12 @@
-import unittest
 import os
-from tests import JinaTestCase
-from jina.executors.indexers.keyvalue.leveldb import LeveldbIndexer
+import unittest
+
+from google.protobuf.json_format import MessageToJson
+
 import jina.proto.jina_pb2 as jina_pb2
 from jina.executors.indexers import BaseIndexer
-from google.protobuf.json_format import MessageToJson
+from jina.executors.indexers.keyvalue.leveldb import LeveldbIndexer
+from tests import JinaTestCase
 
 
 class MyTestCase(JinaTestCase):
diff --git a/tests/executors/indexers/vector/test_annoy.py b/tests/executors/indexers/vector/test_annoy.py
index ecf61cb4f7e0b..410d0bd849e21 100644
--- a/tests/executors/indexers/vector/test_annoy.py
+++ b/tests/executors/indexers/vector/test_annoy.py
@@ -2,6 +2,7 @@
 import unittest
 
 import numpy as np
+
 from jina.executors.indexers import BaseIndexer
 from jina.executors.indexers.vector.annoy import AnnoyIndexer
 from jina.executors.indexers.vector.nmslib import NmslibIndexer
diff --git a/tests/executors/rankers/__init__.py b/tests/executors/rankers/__init__.py
index 3f9a761340e0c..89a6926614930 100644
--- a/tests/executors/rankers/__init__.py
+++ b/tests/executors/rankers/__init__.py
@@ -45,4 +45,3 @@ def test_ranker(self):
         self.assertEqual(doc_idx[1][0], 4294967294)
         # check the number of matched docs
         self.assertEqual(len(doc_idx), 2)
-
diff --git a/tests/test_container.py b/tests/test_container.py
index 3e8ba83d60182..6168ed83be449 100644
--- a/tests/test_container.py
+++ b/tests/test_container.py
@@ -27,7 +27,6 @@ def random_docs(num_docs, chunks_per_doc=5, embed_dim=10):
 built = False
 img_name = 'jina/mwu-encoder'
 
-
 defaulthost = '0.0.0.0'
 localhost = defaulthost if (platform == "linux" or platform == "linux2") else 'host.docker.internal'
 
@@ -44,7 +43,6 @@ def build_image():
 # @unittest.skipUnless(os.getenv('JINA_TEST_CONTAINER', False), 'skip the container test if not set')
 class MyTestCase(JinaTestCase):
 
-
     def tearDown(self) -> None:
         super().tearDown()
         time.sleep(2)
diff --git a/tests/test_flow.py b/tests/test_flow.py
index 872a6f417043f..8ef298711a624 100644
--- a/tests/test_flow.py
+++ b/tests/test_flow.py
@@ -1,19 +1,7 @@
 import unittest
 
 import requests
-from jina import JINA_GLOBAL
-from jina.enums import FlowOptimizeLevel
-from jina.flow import Flow
-from jina.main.checker import NetworkChecker
-from jina.main.parser import set_pea_parser, set_ping_parser
-from jina.main.parser import set_pod_parser
-from jina.peapods.pea import BasePea
-from jina.peapods.pod import BasePod
-from jina.proto import jina_pb2
-from tests import JinaTestCase
-import unittest
 
-import requests
 from jina import JINA_GLOBAL
 from jina.enums import FlowOptimizeLevel
 from jina.flow import Flow
diff --git a/tests/test_index.py b/tests/test_index.py
index 855efa1e7f420..ca2ed77a66a1d 100644
--- a/tests/test_index.py
+++ b/tests/test_index.py
@@ -4,6 +4,7 @@
 import unittest
 
 import numpy as np
+
 from jina.drivers.helper import array2pb
 from jina.enums import FlowOptimizeLevel
 from jina.executors.indexers.vector.numpy import NumpyIndexer
diff --git a/tests/test_index_remote.py b/tests/test_index_remote.py
index 12b81e5180677..a7a558f66e7f2 100644
--- a/tests/test_index_remote.py
+++ b/tests/test_index_remote.py
@@ -4,6 +4,7 @@
 import unittest
 
 import numpy as np
+
 from jina.drivers.helper import array2pb
 from jina.enums import FlowOptimizeLevel
 from jina.executors.indexers.vector.numpy import NumpyIndexer
diff --git a/tests/test_loadbalance.py b/tests/test_loadbalance.py
index 6c734b0611113..c8dfd81e2ecb4 100644
--- a/tests/test_loadbalance.py
+++ b/tests/test_loadbalance.py
@@ -2,16 +2,7 @@
 import time
 
 import numpy as np
-from jina.drivers.helper import array2pb
-from jina.enums import SchedulerType
-from jina.executors.crafters import BaseDocCrafter
-from jina.flow import Flow
-from jina.proto import jina_pb2
-from tests import JinaTestCase
-import os
-import time
 
-import numpy as np
 from jina.drivers.helper import array2pb
 from jina.enums import SchedulerType
 from jina.executors.crafters import BaseDocCrafter
diff --git a/tests/test_quant.py b/tests/test_quant.py
index 038ef0c1e2d82..6be580cd0eeca 100644
--- a/tests/test_quant.py
+++ b/tests/test_quant.py
@@ -1,6 +1,7 @@
 import os
 
 import numpy as np
+
 from jina.drivers.helper import array2pb, pb2array
 from jina.flow import Flow
 from jina.proto import jina_pb2
@@ -52,6 +53,16 @@ def f1(self, quant):
         with f as fl:
             fl.index(random_docs, output_fn=get_output, in_proto=True)
 
+    def f2(self, quant):
+        os.environ['JINA_ARRAY_QUANT'] = quant
+
+        f = Flow(callback_on_body=True, compress_hwm=1024).add(yaml_path='_forward').add(yaml_path='_forward').add(
+            yaml_path='_forward').add(
+            yaml_path='_forward').add(yaml_path='_forward').add(yaml_path='_forward').add(yaml_path='_forward')
+        with f as fl:
+            fl.index(random_docs, output_fn=get_output, in_proto=True)
+
     def test_quant(self):
         for j in ('fp32', 'fp16', 'uint8'):
             self.f1(j)
+            self.f2(j)