Improve statistics validation (#56457)

homeassistant/components/sensor/recorder.py

@@ -562,15 +562,13 @@ def validate_statistics(
         state = hass.states.get(entity_id)
         assert state is not None
 
-        metadata = statistics.get_metadata(hass, entity_id)
-        if not metadata:
-            continue
-
         state_unit = state.attributes.get(ATTR_UNIT_OF_MEASUREMENT)
-        metadata_unit = metadata["unit_of_measurement"]
 
         if device_class not in UNIT_CONVERSIONS:
-
+            metadata = statistics.get_metadata(hass, entity_id)
+            if not metadata:
+                continue
+            metadata_unit = metadata["unit_of_measurement"]
             if state_unit != metadata_unit:
                 validation_result[entity_id].append(
                     statistics.ValidationIssue(

tests/components/recorder/test_websocket_api.py

@@ -86,20 +86,11 @@ async def test_validate_statistics_supported_device_class(
     await hass.async_add_executor_job(hass.data[DATA_INSTANCE].block_till_done)
     await assert_validation_result(client, {})
 
-    # No statistics, invalid state - empty response
+    # No statistics, invalid state - expect error
     hass.states.async_set(
         "sensor.test", 11, attributes={**attributes, **{"unit_of_measurement": "dogs"}}
     )
     await hass.async_add_executor_job(hass.data[DATA_INSTANCE].block_till_done)
-    await assert_validation_result(client, {})
-
-    # Statistics has run, invalid state - expect error
-    await hass.async_add_executor_job(hass.data[DATA_INSTANCE].block_till_done)
-    hass.data[DATA_INSTANCE].do_adhoc_statistics(start=now)
-    hass.states.async_set(
-        "sensor.test", 12, attributes={**attributes, **{"unit_of_measurement": "dogs"}}
-    )
-    await hass.async_add_executor_job(hass.data[DATA_INSTANCE].block_till_done)
     expected = {
         "sensor.test": [
             {
@@ -114,6 +105,15 @@ async def test_validate_statistics_supported_device_class(
     }
     await assert_validation_result(client, expected)
 
+    # Statistics has run, invalid state - expect error
+    await hass.async_add_executor_job(hass.data[DATA_INSTANCE].block_till_done)
+    hass.data[DATA_INSTANCE].do_adhoc_statistics(start=now)
+    hass.states.async_set(
+        "sensor.test", 12, attributes={**attributes, **{"unit_of_measurement": "dogs"}}
+    )
+    await hass.async_add_executor_job(hass.data[DATA_INSTANCE].block_till_done)
+    await assert_validation_result(client, expected)
+
     # Valid state - empty response
     hass.states.async_set(
         "sensor.test", 13, attributes={**attributes, **{"unit_of_measurement": unit}}