Add tests for stdout & stderr in foo_pep333.py example

foo_pep333.py

 import sys
 import os
 import time
+import random
 from pprint import pformat
+random.seed()
 
 def entrypoint(env, start_response):
 	write_body = start_response("200 OK", [('Content-type', 'text/plain')])
 		if not data:
 			break
 	write_body(("Environ data :\n'%s'\n====\n" % pformat(env)).encode())
+	print("Hello world !")
+	print("False error :D", file=sys.stderr)
+	5/0
+	time.sleep(random.randint(0,15)/1000)
+	#time.sleep(random.randint(0,15)/100)
+	#if random.randint(0,100) > 98:
+	#	time.sleep(3)
 	return [b'Hello world !\n']