diff --git a/CHANGELOG.md b/CHANGELOG.md
index ad2b955..e243925 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Pahawh Hmong numeral system
 ### Changed
 - `README.md` updated
+- Test system modified
 ## [1.3] - 2026-01-28
 ### Added
 - English full stop mode
diff --git a/tests/test_conversion.py b/tests/test_conversion.py
index aadd8da..5295551 100644
--- a/tests/test_conversion.py
+++ b/tests/test_conversion.py
@@ -96,6 +96,10 @@
     NumeralSystem.PAHAWH_HMONG: "𖭐𖭑𖭒𖭓𖭔𖭕𖭖𖭗𖭘𖭙",
 }
 
+def test_numeral_system_length():
+    for digits in xnum.params.NUMERAL_MAPS.values():
+        assert len(digits) == 10
+
 
 def test_numeral_system_digits():
     for system, digits in CONVERSION_CASES.items():