diff --git a/src/tests/test.py b/src/tests/test.py
index 1dbf047..88919b7 100644
--- a/src/tests/test.py
+++ b/src/tests/test.py
@@ -75,6 +75,9 @@ class TestCChardet():
         )
     
     def test_github_issue_20(self):
+        """
+        https://github.com/PyYoshi/cChardet/issues/20
+        """
         msg = b'\x8f'
 
         cchardet.detect(msg)