Add compatibility tests for MqttServiceInfo (#60754)

Co-authored-by: epenet <epenet@users.noreply.github.com>

tests/components/mqtt/test_discovery.py

@@ -11,7 +11,11 @@ from homeassistant.components.mqtt.abbreviations import (
     ABBREVIATIONS,
     DEVICE_ABBREVIATIONS,
 )
-from homeassistant.components.mqtt.discovery import ALREADY_DISCOVERED, async_start
+from homeassistant.components.mqtt.discovery import (
+    ALREADY_DISCOVERED,
+    MqttServiceInfo,
+    async_start,
+)
 from homeassistant.const import (
     EVENT_STATE_CHANGED,
     STATE_OFF,
@@ -905,3 +909,27 @@ async def test_mqtt_discovery_unsubscribe_once(hass, mqtt_client_mock, mqtt_mock
         await hass.async_block_till_done()
         await hass.async_block_till_done()
         mqtt_client_mock.unsubscribe.assert_called_once_with("comp/discovery/#")
+
+
+async def test_service_info_compatibility(hass, caplog):
+    """Test compatibility with old-style dict.
+
+    To be removed in 2022.6
+    """
+    discovery_info = MqttServiceInfo(
+        topic="tasmota/discovery/DC4F220848A2/config",
+        payload="",
+        qos=0,
+        retain=False,
+        subscribed_topic="tasmota/discovery/#",
+        timestamp=None,
+    )
+
+    # Ensure first call get logged
+    assert discovery_info["topic"] == "tasmota/discovery/DC4F220848A2/config"
+    assert "Detected code that accessed discovery_info['topic']" in caplog.text
+
+    # Ensure second call doesn't get logged
+    caplog.clear()
+    assert discovery_info["topic"] == "tasmota/discovery/DC4F220848A2/config"
+    assert "Detected code that accessed discovery_info['topic']" not in caplog.text