add client subscribe testing

samples/client_subscribe.py

@@ -0,0 +1,24 @@
+import logging
+from hbmqtt.client._client import MQTTClient
+import asyncio
+
+logger = logging.getLogger(__name__)
+
+C = MQTTClient()
+
+@asyncio.coroutine
+def test_coro():
+    yield from C.connect(uri='mqtt://iot.eclipse.org:1883/', username=None, password=None)
+    yield from C.subscribe([
+                 {'filter': '$SYS/broker/uptime', 'qos': 0x00},
+             ])
+    logger.info("Subscribed")
+
+    yield from asyncio.sleep(60)
+    yield from C.disconnect()
+
+
+if __name__ == '__main__':
+    formatter = "[%(asctime)s] {%(filename)s:%(lineno)d} %(levelname)s - %(message)s"
+    logging.basicConfig(level=logging.DEBUG, format=formatter)
+    asyncio.get_event_loop().run_until_complete(test_coro())