add a quick test to make sure we get the sys.stderr

examples/test.py

@@ -6,6 +6,7 @@
 # Example code from Eventlet sources
 
 import os
+import pprint
 from wsgiref.validate import validator
 import sys
 
@@ -14,6 +15,9 @@ from gunicorn import __version__
 def app(environ, start_response):
     """Simplest possible application object"""
 
+    errors = environ['wsgi.errors']
+    pprint.pprint(('ENVIRON', environ), stream=errors)
+
     data = b'Hello, World!\n'
     status = '200 OK'