diff --git a/tests/common.py b/tests/common.py
index 830b21ed47c..9263cae04e3 100644
--- a/tests/common.py
+++ b/tests/common.py
@@ -124,14 +124,17 @@ def mock_http_component(hass):
     hass.config.components.append('http')
 
 
-def mock_mqtt_component(hass):
-    with mock.patch('homeassistant.components.mqtt.MQTT'):
-        mqtt.setup(hass, {
-            mqtt.DOMAIN: {
-                mqtt.CONF_BROKER: 'mock-broker',
-            }
-        })
-        hass.config.components.append(mqtt.DOMAIN)
+@mock.patch('homeassistant.components.mqtt.MQTT')
+@mock.patch('homeassistant.components.mqtt.MQTT.publish')
+def mock_mqtt_component(hass, mock_mqtt, mock_mqtt_publish):
+    mqtt.setup(hass, {
+        mqtt.DOMAIN: {
+            mqtt.CONF_BROKER: 'mock-broker',
+        }
+    })
+    hass.config.components.append(mqtt.DOMAIN)
+
+    return mock_mqtt_publish
 
 
 class MockHTTP(object):
diff --git a/tests/components/automation/test_mqtt.py b/tests/components/automation/test_mqtt.py
index 174ef91f1c4..516eda53947 100644
--- a/tests/components/automation/test_mqtt.py
+++ b/tests/components/automation/test_mqtt.py
@@ -11,7 +11,7 @@ import homeassistant.components.automation as automation
 from tests.common import mock_mqtt_component, fire_mqtt_message
 
 
-class TestAutomationState(unittest.TestCase):
+class TestAutomationMQTT(unittest.TestCase):
     """ Test the event automation. """
 
     def setUp(self):  # pylint: disable=invalid-name
diff --git a/tests/components/automation/test_zone.py b/tests/components/automation/test_zone.py
index 46a933ebe99..bfb92bb0b1a 100644
--- a/tests/components/automation/test_zone.py
+++ b/tests/components/automation/test_zone.py
@@ -11,7 +11,7 @@ from homeassistant.components import automation, zone
 from tests.common import get_test_home_assistant
 
 
-class TestAutomationEvent(unittest.TestCase):
+class TestAutomationZone(unittest.TestCase):
     """ Test the event automation. """
 
     def setUp(self):  # pylint: disable=invalid-name
diff --git a/tests/components/sensor/__init__.py b/tests/components/sensor/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/components/sensor/test_mqtt.py b/tests/components/sensor/test_mqtt.py
new file mode 100644
index 00000000000..b59ea867c58
--- /dev/null
+++ b/tests/components/sensor/test_mqtt.py
@@ -0,0 +1,41 @@
+"""
+tests.components.sensor.test_mqtt
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Tests mqtt sensor.
+"""
+import unittest
+
+import homeassistant.core as ha
+import homeassistant.components.sensor as sensor
+from tests.common import mock_mqtt_component, fire_mqtt_message
+
+
+class TestSensorMQTT(unittest.TestCase):
+    """ Test the MQTT sensor. """
+
+    def setUp(self):  # pylint: disable=invalid-name
+        self.hass = ha.HomeAssistant()
+        mock_mqtt_component(self.hass)
+
+    def tearDown(self):  # pylint: disable=invalid-name
+        """ Stop down stuff we started. """
+        self.hass.stop()
+
+    def test_setting_sensor_value_via_mqtt_message(self):
+        self.assertTrue(sensor.setup(self.hass, {
+            'sensor': {
+                'platform': 'mqtt',
+                'name': 'test',
+                'state_topic': 'test-topic',
+                'unit_of_measurement': 'fav unit'
+            }
+        }))
+
+        fire_mqtt_message(self.hass, 'test-topic', '100')
+        self.hass.pool.block_till_done()
+        state = self.hass.states.get('sensor.test')
+
+        self.assertEqual('100', state.state)
+        self.assertEqual('fav unit',
+                         state.attributes.get('unit_of_measurement'))
diff --git a/tests/components/switch/__init__.py b/tests/components/switch/__init__.py
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/components/test_switch.py b/tests/components/switch/test_init.py
similarity index 100%
rename from tests/components/test_switch.py
rename to tests/components/switch/test_init.py
diff --git a/tests/components/switch/test_mqtt.py b/tests/components/switch/test_mqtt.py
new file mode 100644
index 00000000000..a09fcf86c58
--- /dev/null
+++ b/tests/components/switch/test_mqtt.py
@@ -0,0 +1,82 @@
+"""
+tests.components.switch.test_mqtt
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Tests mqtt switch.
+"""
+import unittest
+
+from homeassistant.const import STATE_ON, STATE_OFF
+import homeassistant.core as ha
+import homeassistant.components.switch as switch
+from tests.common import mock_mqtt_component, fire_mqtt_message
+
+
+class TestSensorMQTT(unittest.TestCase):
+    """ Test the MQTT switch. """
+
+    def setUp(self):  # pylint: disable=invalid-name
+        self.hass = ha.HomeAssistant()
+        self.mock_publish = mock_mqtt_component(self.hass)
+
+    def tearDown(self):  # pylint: disable=invalid-name
+        """ Stop down stuff we started. """
+        self.hass.stop()
+
+    def test_controlling_state_via_topic(self):
+        self.assertTrue(switch.setup(self.hass, {
+            'switch': {
+                'platform': 'mqtt',
+                'name': 'test',
+                'state_topic': 'state-topic',
+                'command_topic': 'command-topic',
+                'payload_on': 'beer on',
+                'payload_off': 'beer off'
+            }
+        }))
+
+        state = self.hass.states.get('switch.test')
+        self.assertEqual(STATE_OFF, state.state)
+
+        fire_mqtt_message(self.hass, 'state-topic', 'beer on')
+        self.hass.pool.block_till_done()
+
+        state = self.hass.states.get('switch.test')
+        self.assertEqual(STATE_ON, state.state)
+
+        fire_mqtt_message(self.hass, 'state-topic', 'beer off')
+        self.hass.pool.block_till_done()
+
+        state = self.hass.states.get('switch.test')
+        self.assertEqual(STATE_OFF, state.state)
+
+    def test_sending_mqtt_commands_and_optimistic(self):
+        self.assertTrue(switch.setup(self.hass, {
+            'switch': {
+                'platform': 'mqtt',
+                'name': 'test',
+                'command_topic': 'command-topic',
+                'payload_on': 'beer on',
+                'payload_off': 'beer off',
+                'qos': 2
+            }
+        }))
+
+        state = self.hass.states.get('switch.test')
+        self.assertEqual(STATE_OFF, state.state)
+
+        switch.turn_on(self.hass, 'switch.test')
+        self.hass.pool.block_till_done()
+
+        self.assertEqual(('command-topic', 'beer on', 2),
+                         self.mock_publish.mock_calls[-1][1])
+        state = self.hass.states.get('switch.test')
+        self.assertEqual(STATE_ON, state.state)
+
+        switch.turn_off(self.hass, 'switch.test')
+        self.hass.pool.block_till_done()
+
+        self.assertEqual(('command-topic', 'beer off', 2),
+                         self.mock_publish.mock_calls[-1][1])
+        state = self.hass.states.get('switch.test')
+        self.assertEqual(STATE_OFF, state.state)