Fix precedence of StringIO imports for LogTrapTestCase.

io.StringIO doesn't allow byte strings even on python 2, which causes
it to fail with the standard log formatter (but not tornado's "pretty
logging").

Closes #708.

diff --git a/tornado/testing.py b/tornado/testing.py
index b7d2881e91ecdec1267724cd61c2c4538b583095..61c8430611edb028dfc77b61c959179b58248218 100644 (file)
--- a/tornado/testing.py
+++ b/tornado/testing.py
@@ -40,9 +40,9 @@ import socket
 import sys
 
 try:
-    from io import StringIO  # py3
-except ImportError:
     from cStringIO import StringIO  # py2
+except ImportError:
+    from io import StringIO  # py3
 
 # Tornado's own test suite requires the updated unittest module
 # (either py27+ or unittest2) so tornado.test.util enforces