Fix unique_id generation for AtwZoneSensors

The existing unique_id generation generated the same ids for both zones
in 2 zone setups. This change adds a zone-<index> suffix to the id breaking
existing 1 zone setups.

homeassistant/components/melcloud/sensor.py

@@ -165,7 +165,8 @@ class AtwZoneSensor(MelDeviceSensor):
 
     def __init__(self, api: MelCloudDevice, zone: Zone, measurement, definition):
         """Initialize the sensor."""
-        super().__init__(api, measurement, definition)
+        full_measurement = f"{measurement}-zone-{zone.zone_index}"
+        super().__init__(api, full_measurement, definition)
         self._zone = zone
         self._name_slug = f"{api.name} {zone.name}"
 

tests/components/melcloud/test_atw_zone_sensor.py

@@ -0,0 +1,41 @@
+"""Test the MELCloud ATW zone sensor."""
+from unittest.mock import patch
+
+import pytest
+
+from homeassistant.components.melcloud.sensor import AtwZoneSensor
+
+
+@pytest.fixture
+def mock_device():
+    """Mock MELCloud device."""
+    with patch("homeassistant.components.melcloud.MelCloudDevice") as mock:
+        mock.name = "name"
+        mock.device.serial = 1234
+        mock.device.mac = "11:11:11:11:11:11"
+        yield mock
+
+
+@pytest.fixture
+def mock_zone_1():
+    """Mock zone 1."""
+    with patch("pymelcloud.atw_device.Zone") as mock:
+        mock.zone_index = 1
+        yield mock
+
+
+@pytest.fixture
+def mock_zone_2():
+    """Mock zone 2."""
+    with patch("pymelcloud.atw_device.Zone") as mock:
+        mock.zone_index = 2
+        yield mock
+
+
+def test_zone_unique_ids(mock_device, mock_zone_1, mock_zone_2):
+    """Test unique id generation correctness."""
+    sensor_1 = AtwZoneSensor(mock_device, mock_zone_1, "room_temperature", {})
+    assert sensor_1.unique_id == "1234-11:11:11:11:11:11-room_temperature-zone-1"
+
+    sensor_2 = AtwZoneSensor(mock_device, mock_zone_2, "room_temperature", {})
+    assert sensor_2.unique_id == "1234-11:11:11:11:11:11-room_temperature-zone-2"