diff -r 3d1e7792f5a0 Lib/test/test_bytes.py
--- a/Lib/test/test_bytes.py	Fri Apr 15 14:14:05 2016 +0300
+++ b/Lib/test/test_bytes.py	Fri Apr 15 15:36:37 2016 +0200
@@ -492,7 +492,7 @@ class BaseBytesTest:
         b = self.type2test(b'%s / 100 = %d%%')
         a = b % (b'seventy-nine', 79)
         self.assertEqual(a, b'seventy-nine / 100 = 79%')
-        self.assertIs(type(a), bytes)
+        self.assertIs(type(a), self.type2test)
 
     def test_imod(self):
         b = self.type2test(b'hello, %b!')
@@ -504,7 +504,7 @@ class BaseBytesTest:
         b = self.type2test(b'%s / 100 = %d%%')
         b %= (b'seventy-nine', 79)
         self.assertEqual(b, b'seventy-nine / 100 = 79%')
-        self.assertIs(type(b), bytes)
+        self.assertIs(type(b), self.type2test)
 
     def test_rmod(self):
         with self.assertRaises(TypeError):
diff -r 3d1e7792f5a0 Objects/bytesobject.c
--- a/Objects/bytesobject.c	Fri Apr 15 14:14:05 2016 +0300
+++ b/Objects/bytesobject.c	Fri Apr 15 15:36:37 2016 +0200
@@ -4150,7 +4150,12 @@ PyObject *
         result = PyBytes_FromStringAndSize(NULL, 0);
     }
     else if (writer->use_small_buffer) {
-        result = PyBytes_FromStringAndSize(writer->small_buffer, size);
+        if (writer->use_bytearray) {
+            result = PyByteArray_FromStringAndSize(writer->small_buffer, size);
+        }
+        else {
+            result = PyBytes_FromStringAndSize(writer->small_buffer, size);
+        }
     }
     else {
         result = writer->buffer;