Sample test case for a Tornado WS that asynchronously calls a third-party WS

gen.engine async fetch testing

from tornado import ioloop , gen 
from tornado.httpclient import AsyncHTTPClient, HTTPRequest 
from tornado.web import asynchronous, RequestHandler, Application 
from tornado.testing import AsyncHTTPTestCase 
import sys 
from tornado.ioloop import IOLoop 
class MainHandler(RequestHandler): 
    url = u'http://www.google.com' 
    @asynchronous 
    @gen.engine 
    def get(self): 
        http_client = AsyncHTTPClient() 
        request = HTTPRequest(self.url) 
        response = yield gen.Task(http_client.fetch, request) 
        response.rethrow() 
        self.write(repr(response)) 
        self.finish() 
application = Application([(r"/", MainHandler),], debug=True) 
class Test(AsyncHTTPTestCase): 
    def get_app(self): 
        return application 
    def test_task_handler(self): 
        response = self.fetch('/') 
        print >>sys.stderr, response 
    def get_new_ioloop(self): 
        return IOLoop.instance() 
if __name__ == "__main__": 
    application.listen(8888) 
    ioloop.IOLoop.instance().start()