Add helper to report deprecated entity supported features magic numbers (#106602)

tests/helpers/test_entity.py

@@ -3,6 +3,7 @@ import asyncio
 from collections.abc import Iterable
 import dataclasses
 from datetime import timedelta
+from enum import IntFlag
 import logging
 import threading
 from typing import Any
@@ -2025,3 +2026,28 @@ async def test_cached_entity_property_class_attribute(hass: HomeAssistant) -> No
     for ent in entities:
         assert getattr(ent[0], property) == values[1]
         assert getattr(ent[1], property) == values[0]
+
+
+async def test_entity_report_deprecated_supported_features_values(
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test reporting deprecated supported feature values only happens once."""
+    ent = entity.Entity()
+
+    class MockEntityFeatures(IntFlag):
+        VALUE1 = 1
+        VALUE2 = 2
+
+    ent._report_deprecated_supported_features_values(MockEntityFeatures(2))
+    assert (
+        "is using deprecated supported features values which will be removed"
+        in caplog.text
+    )
+    assert "MockEntityFeatures.VALUE2" in caplog.text
+
+    caplog.clear()
+    ent._report_deprecated_supported_features_values(MockEntityFeatures(2))
+    assert (
+        "is using deprecated supported features values which will be removed"
+        not in caplog.text
+    )