add coverage

tests/coverage_server.py

@@ -0,0 +1,23 @@
+#!/usr/bin/env python
+
+import tornado.ioloop
+import tornado.web
+import urllib
+
+
+class MainHandler(tornado.web.RequestHandler):
+    def get(self):
+        with open('/tmp/shadowsocks-coverage', 'rb') as f:
+            coverage = f.read().strip()
+            self.redirect(('https://img.shields.io/badge/'
+                           'coverage-%s-brightgreen.svg'
+                           '?style=flat') %
+                          urllib.quote(coverage))
+
+application = tornado.web.Application([
+    (r"/shadowsocks", MainHandler),
+])
+
+if __name__ == "__main__":
+    application.listen(8888, address='127.0.0.1')
+    tornado.ioloop.IOLoop.instance().start()