Optimize entity icon memory usage with USE_ENTITY_ICON flag (#9337)

tests/integration/fixtures/entity_icon.yaml

@@ -0,0 +1,78 @@
+esphome:
+  name: icon-test
+
+host:
+
+api:
+
+logger:
+
+# Test entities with custom icons
+sensor:
+  - platform: template
+    name: "Sensor With Icon"
+    icon: "mdi:temperature-celsius"
+    unit_of_measurement: "°C"
+    update_interval: 1s
+    lambda: |-
+      return 25.5;
+
+  - platform: template
+    name: "Sensor Without Icon"
+    unit_of_measurement: "%"
+    update_interval: 1s
+    lambda: |-
+      return 50.0;
+
+binary_sensor:
+  - platform: template
+    name: "Binary Sensor With Icon"
+    icon: "mdi:motion-sensor"
+    lambda: |-
+      return true;
+
+  - platform: template
+    name: "Binary Sensor Without Icon"
+    lambda: |-
+      return false;
+
+text_sensor:
+  - platform: template
+    name: "Text Sensor With Icon"
+    icon: "mdi:text-box"
+    lambda: |-
+      return {"Hello Icons"};
+
+switch:
+  - platform: template
+    name: "Switch With Icon"
+    icon: "mdi:toggle-switch"
+    optimistic: true
+
+button:
+  - platform: template
+    name: "Button With Icon"
+    icon: "mdi:gesture-tap-button"
+    on_press:
+      - logger.log: "Button with icon pressed"
+
+number:
+  - platform: template
+    name: "Number With Icon"
+    icon: "mdi:numeric"
+    initial_value: 42
+    min_value: 0
+    max_value: 100
+    step: 1
+    optimistic: true
+
+select:
+  - platform: template
+    name: "Select With Icon"
+    icon: "mdi:format-list-bulleted"
+    options:
+      - "Option A"
+      - "Option B"
+      - "Option C"
+    initial_option: "Option A"
+    optimistic: true

tests/integration/test_entity_icon.py

@@ -0,0 +1,97 @@
+"""Integration test for entity icons with USE_ENTITY_ICON feature."""
+
+from __future__ import annotations
+
+import asyncio
+
+from aioesphomeapi import EntityState
+import pytest
+
+from .types import APIClientConnectedFactory, RunCompiledFunction
+
+
+@pytest.mark.asyncio
+async def test_entity_icon(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """Test that entities with custom icons work correctly with USE_ENTITY_ICON."""
+    # Write, compile and run the ESPHome device, then connect to API
+    async with run_compiled(yaml_config), api_client_connected() as client:
+        # Get all entities
+        entities = await client.list_entities_services()
+
+        # Create a map of entity names to entity info
+        entity_map = {entity.name: entity for entity in entities[0]}
+
+        # Test entities with icons
+        icon_test_cases = [
+            # (entity_name, expected_icon)
+            ("Sensor With Icon", "mdi:temperature-celsius"),
+            ("Binary Sensor With Icon", "mdi:motion-sensor"),
+            ("Text Sensor With Icon", "mdi:text-box"),
+            ("Switch With Icon", "mdi:toggle-switch"),
+            ("Button With Icon", "mdi:gesture-tap-button"),
+            ("Number With Icon", "mdi:numeric"),
+            ("Select With Icon", "mdi:format-list-bulleted"),
+        ]
+
+        # Test entities without icons (should have empty string)
+        no_icon_test_cases = [
+            "Sensor Without Icon",
+            "Binary Sensor Without Icon",
+        ]
+
+        # Verify entities with icons
+        for entity_name, expected_icon in icon_test_cases:
+            assert entity_name in entity_map, (
+                f"Entity '{entity_name}' not found in API response"
+            )
+            entity = entity_map[entity_name]
+
+            # Check icon field
+            assert hasattr(entity, "icon"), (
+                f"{entity_name}: Entity should have icon attribute"
+            )
+            assert entity.icon == expected_icon, (
+                f"{entity_name}: icon mismatch - "
+                f"expected '{expected_icon}', got '{entity.icon}'"
+            )
+
+        # Verify entities without icons
+        for entity_name in no_icon_test_cases:
+            assert entity_name in entity_map, (
+                f"Entity '{entity_name}' not found in API response"
+            )
+            entity = entity_map[entity_name]
+
+            # Check icon field is empty
+            assert hasattr(entity, "icon"), (
+                f"{entity_name}: Entity should have icon attribute"
+            )
+            assert entity.icon == "", (
+                f"{entity_name}: icon should be empty string for entities without icons, "
+                f"got '{entity.icon}'"
+            )
+
+        # Subscribe to states to ensure everything works normally
+        states: dict[int, EntityState] = {}
+        state_received = asyncio.Event()
+
+        def on_state(state: EntityState) -> None:
+            states[state.key] = state
+            state_received.set()
+
+        client.subscribe_states(on_state)
+
+        # Wait for states
+        try:
+            await asyncio.wait_for(state_received.wait(), timeout=5.0)
+        except asyncio.TimeoutError:
+            pytest.fail("No states received within 5 seconds")
+
+        # Verify we received states
+        assert len(states) > 0, (
+            "No states received - entities may not be working correctly"
+        )