[3.12] gh-131339: test PyBytes_Size for a zero-size bytes object (GH-131340) (#131344)

gh-131339: test PyBytes_Size for a zero-size bytes object (GH-131340)
(cherry picked from commit 3ae67ba)

Co-authored-by: Nybblista <[email protected]>

Author: miss-islington

Lib/test/test_capi/test_bytes.py

@@ -92,6 +92,7 @@ def test_size(self):
         # Test PyBytes_Size()
         size = _testcapi.bytes_size
 
+        self.assertEqual(size(b''), 0)
         self.assertEqual(size(b'abc'), 3)
         self.assertEqual(size(BytesSubclass(b'abc')), 3)
         self.assertRaises(TypeError, size, bytearray(b'abc'))