diff --git a/tests/validators/test_length.py b/tests/validators/test_length.py
index 06be52d9..807b0b9a 100644
--- a/tests/validators/test_length.py
+++ b/tests/validators/test_length.py
@@ -58,6 +58,7 @@ def test_length_messages(dummy_form, dummy_field, validator, message):
 
     assert message in str(e.value)
 
+
 @pytest.mark.parametrize("min_v, max_v", [(-1, 5)])
 def test_null_str_pass(min_v, max_v, dummy_form, dummy_field):
     """
@@ -68,6 +69,7 @@ def test_null_str_pass(min_v, max_v, dummy_form, dummy_field):
     validator = length(min_v, max_v)
     validator(dummy_form, dummy_field)
 
+
 @pytest.mark.parametrize("min_v, max_v", [(0, 5), (0, -1)])
 def test_null_str_fail(min_v, max_v, dummy_form, dummy_field):
     """
@@ -79,6 +81,7 @@ def test_null_str_fail(min_v, max_v, dummy_form, dummy_field):
     with pytest.raises(ValidationError):
         validator(dummy_form, dummy_field)
 
+
 @pytest.mark.parametrize("min_v, max_v", [(0, 5), (0, -1)])
 def test_empty_str_pass(min_v, max_v, dummy_form, dummy_field):
     """