diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
index a103a7d..cd82fa6 100644
--- a/Lib/test/test_bytes.py
+++ b/Lib/test/test_bytes.py
@@ -507,6 +507,11 @@
         a = b % (b'seventy-nine', 79)
         self.assertEqual(a, b'seventy-nine / 100 = 79%')
         self.assertIs(type(a), self.type2test)
+        # issue 29714
+        b = self.type2test(b'hello,\x00%b!')
+        b = b % b'world'
+        self.assertEqual(b, b'hello,\x00world!')
+        self.assertIs(type(b), self.type2test)
 
     def test_imod(self):
         b = self.type2test(b'hello, %b!')
@@ -519,6 +524,11 @@
         b %= (b'seventy-nine', 79)
         self.assertEqual(b, b'seventy-nine / 100 = 79%')
         self.assertIs(type(b), self.type2test)
+        # issue 29714
+        b = self.type2test(b'hello,\x00%b!')
+        b %= b'world'
+        self.assertEqual(b, b'hello,\x00world!')
+        self.assertIs(type(b), self.type2test)
 
     def test_rmod(self):
         with self.assertRaises(TypeError):