Device tracker component & platform validation. No more home_range. (#2908)

* Device tracker component & platform validation. No more home_range.

* Mock, bluetooth

* Renamed _CONFIG_SCHEMA. Raise warning for #1606

* test duplicates

* Fix assert

* Coverage

* Typing

* T fixes

tests/components/device_tracker/test_mqtt.py

@@ -1,5 +1,7 @@
 """The tests for the MQTT device tracker platform."""
 import unittest
+from unittest.mock import patch
+import logging
 import os
 
 from homeassistant.bootstrap import _setup_component
@@ -9,6 +11,8 @@ from homeassistant.const import CONF_PLATFORM
 from tests.common import (
     get_test_home_assistant, mock_mqtt_component, fire_mqtt_message)
 
+_LOGGER = logging.getLogger(__name__)
+
 
 class TestComponentsDeviceTrackerMQTT(unittest.TestCase):
     """Test MQTT device tracker platform."""
@@ -25,6 +29,27 @@ class TestComponentsDeviceTrackerMQTT(unittest.TestCase):
         except FileNotFoundError:
             pass
 
+    def test_ensure_device_tracker_platform_validation(self): \
+            # pylint: disable=invalid-name
+        """Test if platform validation was done."""
+        def mock_setup_scanner(hass, config, see):
+            """Check that Qos was added by validation."""
+            self.assertTrue('qos' in config)
+
+        with patch('homeassistant.components.device_tracker.mqtt.'
+                   'setup_scanner', side_effect=mock_setup_scanner) as mock_sp:
+
+            dev_id = 'paulus'
+            topic = '/location/paulus'
+            self.hass.config.components = ['mqtt', 'zone']
+            assert _setup_component(self.hass, device_tracker.DOMAIN, {
+                device_tracker.DOMAIN: {
+                    CONF_PLATFORM: 'mqtt',
+                    'devices': {dev_id: topic}
+                }
+            })
+            assert mock_sp.call_count == 1
+
     def test_new_message(self):
         """Test new message."""
         dev_id = 'paulus'