Raise ValueError for incorrect arguments.

This improves error reporting in that case.

src/sequences/__init__.py

@@ -71,8 +71,8 @@ def get_next_value(
     # Inner import because models cannot be imported before their application.
     from .models import Sequence
 
-    if reset_value is not None:
-        assert initial_value < reset_value
+    if reset_value is not None and reset_value <= initial_value:
+        raise ValueError("reset_value must be greater than initial_value")
 
     if using is None:
         using = router.db_for_write(Sequence)
@@ -170,8 +170,8 @@ def __init__(
         *,
         using=None,
     ):
-        if reset_value is not None:
-            assert initial_value < reset_value
+        if reset_value is not None and reset_value <= initial_value:
+            raise ValueError("reset_value must be greater than initial_value")
         self.sequence_name = sequence_name
         self.initial_value = initial_value
         self.reset_value = reset_value

tests/test_sequences.py

@@ -48,7 +48,7 @@ def test_functions_reset_value(self):
         self.assertEqual(get_next_value("reference", 1, 3), 2)
 
     def test_functions_reset_value_smaller_than_initial_value(self):
-        with self.assertRaises(AssertionError):
+        with self.assertRaises(ValueError):
             get_next_value("error", initial_value=1, reset_value=1)
 
     def test_class_defaults(self):
@@ -101,7 +101,7 @@ def test_class_reset_value(self):
         self.assertEqual(reference_seq.get_next_value(), 2)
 
     def test_class_reset_value_smaller_than_initial_value(self):
-        with self.assertRaises(AssertionError):
+        with self.assertRaises(ValueError):
             Sequence("error", initial_value=1, reset_value=1)