diff --git a/swh/storage/tests/server_testing.py b/swh/storage/tests/server_testing.py
index 61277d30..33e7d9aa 100644
--- a/swh/storage/tests/server_testing.py
+++ b/swh/storage/tests/server_testing.py
@@ -1,80 +1,80 @@
 # Copyright (C) 2015  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import multiprocessing
 import socket
 import time
 
 from urllib.request import urlopen
 
 
 class ServerTestFixture():
     """ Base class for http client/server testing.
 
     Mix this in a test class in order to have access to an http flask
     server running in background.
 
     Note that the subclass should define a dictionary in self.config
     that contains the flask server config.
     And a flask application in self.app that corresponds to the type of
     server the tested client needs.
 
     To ensure test isolation, each test will run in a different server
     and a different repertory.
 
     In order to correctly work, the subclass must call the parents class's
     setUp() and tearDown() methods.
     """
 
     def setUp(self):
         super().setUp()
         self.start_server()
 
     def tearDown(self):
         self.stop_server()
         super().tearDown()
 
     def url(self):
         return 'http://127.0.0.1:%d/' % self.port
 
     def start_server(self):
         """ Spawn the API server using multiprocessing.
         """
         self.process = None
 
         # WSGI app configuration
         for key, value in self.config.items():
             self.app.config[key] = value
         # Get an available port number
         sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         sock.bind(('127.0.0.1', 0))
         self.port = sock.getsockname()[1]
         sock.close()
 
         # Worker function for multiprocessing
         def worker(app, port):
             return app.run(port=port, use_reloader=False)
 
         self.process = multiprocessing.Process(
             target=worker, args=(self.app, self.port)
         )
         self.process.start()
 
         # Wait max 5 seconds for server to spawn
         i = 0
-        while i < 20:
+        while i < 500:
             try:
                 urlopen(self.url())
             except Exception:
                 i += 1
-                time.sleep(0.25)
+                time.sleep(0.01)
             else:
                 return
 
     def stop_server(self):
         """ Terminate the API server's process.
         """
         if self.process:
             self.process.terminate()