gistfile1.py

import threading
from wsgiref.simple_server import make_server

def serve_once(handler, port=4442):
    """ Single serving web server
    
    Creates a web server in another thread that will output the result of 
    handler for a single request. Returns a URL to hit the web server.
    """
    def app(e, start):
        start("200 OK", [])
        return [handler()]
    httpd = make_server('', port, app)
    threading.Thread(target=httpd.handle_request).start()
    return "http://localhost:%s/" % port

if __name__ == '__main__':
    import urllib
    url = serve_once(lambda: 'foobar')
    assert 'foobar' in urllib.urlopen(url).read()