diff --git a/.coveragerc b/.coveragerc
index 1dc94450eac..956bdd023e8 100644
--- a/.coveragerc
+++ b/.coveragerc
@@ -85,3 +85,6 @@ exclude_lines =
     # Don't complain if tests don't hit defensive assertion code:
     raise AssertionError
     raise NotImplementedError
+
+    # The MQTT client is mocked
+    class MQTT
diff --git a/homeassistant/__init__.py b/homeassistant/__init__.py
index bf21dc0a15d..afc4ea8375f 100644
--- a/homeassistant/__init__.py
+++ b/homeassistant/__init__.py
@@ -628,12 +628,12 @@ class ServiceRegistry(object):
     def _execute_service(self, service_and_call):
         """ Executes a service and fires a SERVICE_EXECUTED event. """
         service, call = service_and_call
-
         service(call)
 
-        self._bus.fire(
-            EVENT_SERVICE_EXECUTED,
-            {ATTR_SERVICE_CALL_ID: call.data[ATTR_SERVICE_CALL_ID]})
+        if ATTR_SERVICE_CALL_ID in call.data:
+            self._bus.fire(
+                EVENT_SERVICE_EXECUTED,
+                {ATTR_SERVICE_CALL_ID: call.data[ATTR_SERVICE_CALL_ID]})
 
     def _generate_unique_id(self):
         """ Generates a unique service call id. """
diff --git a/tests/components/test_mqtt.py b/tests/components/test_mqtt.py
index 671cae4237f..4c3dbb1d20a 100644
--- a/tests/components/test_mqtt.py
+++ b/tests/components/test_mqtt.py
@@ -5,19 +5,23 @@ tests.test_component_mqtt
 Tests MQTT component.
 """
 import unittest
+from unittest import mock
+import socket
 
-import homeassistant as ha
 import homeassistant.components.mqtt as mqtt
-from homeassistant.const import EVENT_CALL_SERVICE
+from homeassistant.const import (
+    EVENT_CALL_SERVICE, ATTR_DOMAIN, ATTR_SERVICE, EVENT_HOMEASSISTANT_START,
+    EVENT_HOMEASSISTANT_STOP)
 
-from tests.common import mock_mqtt_component, fire_mqtt_message
+from tests.common import (
+    get_test_home_assistant, mock_mqtt_component, fire_mqtt_message)
 
 
 class TestDemo(unittest.TestCase):
     """ Test the demo module. """
 
     def setUp(self):  # pylint: disable=invalid-name
-        self.hass = ha.HomeAssistant()
+        self.hass = get_test_home_assistant(1)
         mock_mqtt_component(self.hass)
         self.calls = []
 
@@ -28,6 +32,28 @@ class TestDemo(unittest.TestCase):
     def record_calls(self, *args):
         self.calls.append(args)
 
+    def test_client_starts_on_home_assistant_start(self):
+        self.hass.bus.fire(EVENT_HOMEASSISTANT_START)
+        self.hass.pool.block_till_done()
+        self.assertTrue(mqtt.MQTT_CLIENT.start.called)
+
+    def test_client_stops_on_home_assistant_start(self):
+        self.hass.bus.fire(EVENT_HOMEASSISTANT_START)
+        self.hass.pool.block_till_done()
+        self.hass.bus.fire(EVENT_HOMEASSISTANT_STOP)
+        self.hass.pool.block_till_done()
+        self.assertTrue(mqtt.MQTT_CLIENT.stop.called)
+
+    def test_setup_fails_if_no_broker_config(self):
+        self.assertFalse(mqtt.setup(self.hass, {mqtt.DOMAIN: {}}))
+
+    def test_setup_fails_if_no_connect_broker(self):
+        with mock.patch('homeassistant.components.mqtt.MQTT',
+                        side_effect=socket.error()):
+            self.assertFalse(mqtt.setup(self.hass, {mqtt.DOMAIN: {
+                mqtt.CONF_BROKER: 'test-broker',
+            }}))
+
     def test_publish_calls_service(self):
         self.hass.bus.listen_once(EVENT_CALL_SERVICE, self.record_calls)
 
@@ -39,6 +65,14 @@ class TestDemo(unittest.TestCase):
         self.assertEqual('test-topic', self.calls[0][0].data[mqtt.ATTR_TOPIC])
         self.assertEqual('test-payload', self.calls[0][0].data[mqtt.ATTR_PAYLOAD])
 
+    def test_service_call_without_topic_does_not_publush(self):
+        self.hass.bus.fire(EVENT_CALL_SERVICE, {
+            ATTR_DOMAIN: mqtt.DOMAIN,
+            ATTR_SERVICE: mqtt.SERVICE_PUBLISH
+        })
+        self.hass.pool.block_till_done()
+        self.assertTrue(not mqtt.MQTT_CLIENT.publish.called)
+
     def test_subscribe_topic(self):
         mqtt.subscribe(self.hass, 'test-topic', self.record_calls)