diff --git a/src/tests/test_gf256.py b/src/tests/test_gf256.py
--- a/src/tests/test_gf256.py
+++ b/src/tests/test_gf256.py
@@ -1,3 +1,5 @@
+# GNU GPLv3, see LICENSE
+
 import random
 import unittest
 from unittest import TestCase