diff --git a/brainpy/_src/tests/test_mixin.py b/brainpy/_src/tests/test_mixin.py
index be8eaade6..5fbab7b9f 100644
--- a/brainpy/_src/tests/test_mixin.py
+++ b/brainpy/_src/tests/test_mixin.py
@@ -42,9 +42,12 @@ class TestDelayRegister(unittest.TestCase):
   def test2(self):
     bp.share.save(i=0)
     lif = bp.dyn.Lif(10)
-    lif.register_local_delay('a', 10.)
-    data = lif.get_local_delay('a')
+    lif.register_local_delay('spike', 'a', 10.)
+    data = lif.get_local_delay('spike', 'a')
     self.assertTrue(bm.allclose(data, bm.zeros(10)))
 
+    with self.assertRaises(AttributeError):
+      lif.register_local_delay('a', 'a', 10.)
+