diff --git a/tests/test_register_custom_ops.py b/tests/test_register_custom_ops.py
index 1114e7cf0..e47104c3a 100644
--- a/tests/test_register_custom_ops.py
+++ b/tests/test_register_custom_ops.py
@@ -60,11 +60,11 @@ class Distance(PairOperator):
         series_right = self.feature_right.load(instrument, start_index, end_index, freq)
         return np.abs(series_left - series_right)
 
+OpsList = [Diff, Distance]
+Operators.register(OpsList)
 
 class TestRegiterCustomOps(TestAutoData):
     def test_regiter_custom_ops(self):
-        OpsList = [Diff, Distance]
-        Operators.register(OpsList)
         instruments = ["SH600000"]
         fields = ["Diff($close)", "Distance($close, Ref($close, 1))"]
         print(D.features(instruments, fields, start_time="2010-01-01", end_time="2017-12-31", freq="day"))