Switch wsgiref to io.{StringIO,BytesIO}. This shuts up the test failures.
(I'm not sure about it actually working though.)
diff --git a/Lib/wsgiref/util.py b/Lib/wsgiref/util.py
index 5b44eda..a4ca02f 100644
--- a/Lib/wsgiref/util.py
+++ b/Lib/wsgiref/util.py
@@ -149,7 +149,7 @@
environ.setdefault('wsgi.multithread', 0)
environ.setdefault('wsgi.multiprocess', 0)
- from StringIO import StringIO
+ from io import StringIO
environ.setdefault('wsgi.input', StringIO(""))
environ.setdefault('wsgi.errors', StringIO())
environ.setdefault('wsgi.url_scheme',guess_scheme(environ))