bpo-44018: random.seed() no longer mutates its inputs (GH-25856) (GH-25872)

diff --git a/Lib/test/test_random.py b/Lib/test/test_random.py
index 6690886..5354edd 100644
--- a/Lib/test/test_random.py
+++ b/Lib/test/test_random.py
@@ -57,6 +57,11 @@ def __hash__(self):
         self.assertRaises(TypeError, self.gen.seed, 1, 2, 3, 4)
         self.assertRaises(TypeError, type(self.gen), [])
 
+    def test_seed_no_mutate_bug_44018(self):
+        a = bytearray(b'1234')
+        self.gen.seed(a)
+        self.assertEqual(a, bytearray(b'1234'))
+
     @unittest.mock.patch('random._urandom') # os.urandom
     def test_seed_when_randomness_source_not_found(self, urandom_mock):
         # Random.seed() uses time.time() when an operating system specific