diff --git a/tests/mosquitto.org.crt b/tests/mosquitto.org.crt
deleted file mode 100644
index b8535e8..0000000
--- a/tests/mosquitto.org.crt
+++ /dev/null
@@ -1,18 +0,0 @@
------BEGIN CERTIFICATE-----
-MIIC8DCCAlmgAwIBAgIJAOD63PlXjJi8MA0GCSqGSIb3DQEBBQUAMIGQMQswCQYD
-VQQGEwJHQjEXMBUGA1UECAwOVW5pdGVkIEtpbmdkb20xDjAMBgNVBAcMBURlcmJ5
-MRIwEAYDVQQKDAlNb3NxdWl0dG8xCzAJBgNVBAsMAkNBMRYwFAYDVQQDDA1tb3Nx
-dWl0dG8ub3JnMR8wHQYJKoZIhvcNAQkBFhByb2dlckBhdGNob28ub3JnMB4XDTEy
-MDYyOTIyMTE1OVoXDTIyMDYyNzIyMTE1OVowgZAxCzAJBgNVBAYTAkdCMRcwFQYD
-VQQIDA5Vbml0ZWQgS2luZ2RvbTEOMAwGA1UEBwwFRGVyYnkxEjAQBgNVBAoMCU1v
-c3F1aXR0bzELMAkGA1UECwwCQ0ExFjAUBgNVBAMMDW1vc3F1aXR0by5vcmcxHzAd
-BgkqhkiG9w0BCQEWEHJvZ2VyQGF0Y2hvby5vcmcwgZ8wDQYJKoZIhvcNAQEBBQAD
-gY0AMIGJAoGBAMYkLmX7SqOT/jJCZoQ1NWdCrr/pq47m3xxyXcI+FLEmwbE3R9vM
-rE6sRbP2S89pfrCt7iuITXPKycpUcIU0mtcT1OqxGBV2lb6RaOT2gC5pxyGaFJ+h
-A+GIbdYKO3JprPxSBoRponZJvDGEZuM3N7p3S/lRoi7G5wG5mvUmaE5RAgMBAAGj
-UDBOMB0GA1UdDgQWBBTad2QneVztIPQzRRGj6ZHKqJTv5jAfBgNVHSMEGDAWgBTa
-d2QneVztIPQzRRGj6ZHKqJTv5jAMBgNVHRMEBTADAQH/MA0GCSqGSIb3DQEBBQUA
-A4GBAAqw1rK4NlRUCUBLhEFUQasjP7xfFqlVbE2cRy0Rs4o3KS0JwzQVBwG85xge
-REyPOFdGdhBY2P1FNRy0MDr6xr+D2ZOwxs63dG1nnAnWZg7qwoLgpZ4fESPD3PkA
-1ZgKJc2zbSQ9fCPxt2W3mdVav66c6fsb7els2W2Iz7gERJSX
------END CERTIFICATE-----
diff --git a/tests/test_client.py b/tests/test_client.py
index cdc3f8b..72d333f 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -5,6 +5,9 @@ import unittest
 import asyncio
 import os
 import logging
+import urllib.request
+import tempfile
+import shutil
 from hbmqtt.client import MQTTClient, ConnectException
 from hbmqtt.broker import Broker
 from hbmqtt.mqtt.constants import QOS_0, QOS_1, QOS_2
@@ -43,8 +46,15 @@ class MQTTClientTest(unittest.TestCase):
         self.loop = asyncio.new_event_loop()
         asyncio.set_event_loop(self.loop)
 
+        self.temp_dir = tempfile.mkdtemp(prefix='hbmqtt-test-')
+        url = "http://test.mosquitto.org/ssl/mosquitto.org.crt"
+        self.ca_file = os.path.join(self.temp_dir, 'mosquitto.org.crt')
+        urllib.request.urlretrieve(url, self.ca_file)
+        log.info("stored mosquitto cert at %s" % self.ca_file)
+
     def tearDown(self):
         self.loop.close()
+        shutil.rmtree(self.temp_dir)
 
     def test_connect_tcp(self):
         @asyncio.coroutine
@@ -68,8 +78,7 @@ class MQTTClientTest(unittest.TestCase):
         def test_coro():
             try:
                 client = MQTTClient(config={'check_hostname': False})
-                ca = os.path.join(os.path.dirname(os.path.realpath(__file__)), 'mosquitto.org.crt')
-                yield from client.connect('mqtts://test.mosquitto.org/', cafile=ca)
+                yield from client.connect('mqtts://test.mosquitto.org/', cafile=self.ca_file)
                 self.assertIsNotNone(client.session)
                 yield from client.disconnect()
                 future.set_result(True)
@@ -115,7 +124,6 @@ class MQTTClientTest(unittest.TestCase):
         self.loop.run_until_complete(test_coro())
         if future.exception():
             raise future.exception()
-            raise future.exception()
 
     def test_reconnect_ws_retain_username_password(self):
         @asyncio.coroutine
@@ -148,8 +156,7 @@ class MQTTClientTest(unittest.TestCase):
                 broker = Broker(broker_config, plugin_namespace="hbmqtt.test.plugins")
                 yield from broker.start()
                 client = MQTTClient()
-                ca = os.path.join(os.path.dirname(os.path.realpath(__file__)), 'mosquitto.org.crt')
-                yield from client.connect('ws://127.0.0.1:8081/', cafile=ca)
+                yield from client.connect('ws://127.0.0.1:8081/', cafile=self.ca_file)
                 self.assertIsNotNone(client.session)
                 yield from client.disconnect()
                 yield from broker.shutdown()