requests is a required dependency for the tests

setup.py

@@ -59,10 +59,11 @@ setup(
     install_requires = [
         'pyyaml',
         'requires',
+        'requests',
     ],
     extras_require = {
         'Support for Apache Kafka backend': ['kafka-python'],
-        'Support for Pushbullet backend': ['requests', 'websocket-client'],
+        'Support for Pushbullet backend': ['websocket-client'],
         'Support for HTTP backend': ['flask'],
         'Support for Philips Hue plugin': ['phue'],
         'Support for MPD/Mopidy music server plugin': ['python-mpd2'],