Fix "BytesWarning: str() on a bytes instance"
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index 1e97bac..8ec3d71 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -1081,7 +1081,8 @@
stdout=subprocess.PIPE, stderr=subprocess.PIPE)
stdout, stderr = p.communicate()
self.assertEqual(0, p.returncode, "sigchild_ignore.py exited"
- " non-zero with this error:\n%s" % stderr)
+ " non-zero with this error:\n%s" %
+ stderr.decode('utf8'))
@unittest.skipUnless(mswindows, "Windows specific tests")