Add unique_id to mqtt camera (#16569)

* Add unique_id to mqtt camera

* Remove whitespaces

* Add test for unique_id

* Add blank line

homeassistant/components/camera/mqtt.py

@@ -19,12 +19,14 @@ from homeassistant.helpers import config_validation as cv
 _LOGGER = logging.getLogger(__name__)
 
 CONF_TOPIC = 'topic'
+CONF_UNIQUE_ID = 'unique_id'
 DEFAULT_NAME = 'MQTT Camera'
 
 DEPENDENCIES = ['mqtt']
 
 PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
     vol.Required(CONF_TOPIC): mqtt.valid_subscribe_topic,
+    vol.Optional(CONF_UNIQUE_ID): cv.string,
     vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string
 })
 
@@ -38,6 +40,7 @@ def async_setup_platform(hass, config, async_add_entities,
 
     async_add_entities([MqttCamera(
         config.get(CONF_NAME),
+        config.get(CONF_UNIQUE_ID),
         config.get(CONF_TOPIC)
     )])
 
@@ -45,11 +48,12 @@ def async_setup_platform(hass, config, async_add_entities,
 class MqttCamera(Camera):
     """representation of a MQTT camera."""
 
-    def __init__(self, name, topic):
+    def __init__(self, name, unique_id, topic):
         """Initialize the MQTT Camera."""
         super().__init__()
 
         self._name = name
+        self._unique_id = unique_id
         self._topic = topic
         self._qos = 0
         self._last_image = None
@@ -64,6 +68,11 @@ class MqttCamera(Camera):
         """Return the name of this camera."""
         return self._name
 
+    @property
+    def unique_id(self):
+        """Return a unique ID."""
+        return self._unique_id
+
     @asyncio.coroutine
     def async_added_to_hass(self):
         """Subscribe MQTT events."""

tests/components/camera/test_mqtt.py

@@ -29,3 +29,26 @@ def test_run_camera_setup(hass, aiohttp_client):
     assert resp.status == 200
     body = yield from resp.text()
     assert body == 'beer'
+
+
+@asyncio.coroutine
+def test_unique_id(hass):
+    """Test unique id option only creates one camera per unique_id."""
+    yield from async_mock_mqtt_component(hass)
+    yield from async_setup_component(hass, 'camera', {
+        'camera': [{
+            'platform': 'mqtt',
+            'name': 'Test Camera 1',
+            'topic': 'test-topic',
+            'unique_id': 'TOTALLY_UNIQUE'
+        }, {
+            'platform': 'mqtt',
+            'name': 'Test Camera 2',
+            'topic': 'test-topic',
+            'unique_id': 'TOTALLY_UNIQUE'
+        }]
+    })
+
+    async_fire_mqtt_message(hass, 'test-topic', 'payload')
+    yield from hass.async_block_till_done()
+    assert len(hass.states.async_all()) == 1