ESPHome: Add Date Entity support (#112475)

* ESPHome: Add Date Entity support

* Formatting

* Add missing state test

tests/components/esphome/test_date.py

@@ -0,0 +1,76 @@
+"""Test ESPHome dates."""
+
+from unittest.mock import call
+
+from aioesphomeapi import APIClient, DateInfo, DateState
+
+from homeassistant.components.date import (
+    ATTR_DATE,
+    DOMAIN as DATE_DOMAIN,
+    SERVICE_SET_VALUE,
+)
+from homeassistant.const import ATTR_ENTITY_ID, STATE_UNKNOWN
+from homeassistant.core import HomeAssistant
+
+
+async def test_generic_date_entity(
+    hass: HomeAssistant,
+    mock_client: APIClient,
+    mock_generic_device_entry,
+) -> None:
+    """Test a generic date entity."""
+    entity_info = [
+        DateInfo(
+            object_id="mydate",
+            key=1,
+            name="my date",
+            unique_id="my_date",
+        )
+    ]
+    states = [DateState(key=1, year=2024, month=12, day=31)]
+    user_service = []
+    await mock_generic_device_entry(
+        mock_client=mock_client,
+        entity_info=entity_info,
+        user_service=user_service,
+        states=states,
+    )
+    state = hass.states.get("date.test_mydate")
+    assert state is not None
+    assert state.state == "2024-12-31"
+
+    await hass.services.async_call(
+        DATE_DOMAIN,
+        SERVICE_SET_VALUE,
+        {ATTR_ENTITY_ID: "date.test_mydate", ATTR_DATE: "1999-01-01"},
+        blocking=True,
+    )
+    mock_client.date_command.assert_has_calls([call(1, 1999, 1, 1)])
+    mock_client.date_command.reset_mock()
+
+
+async def test_generic_date_missing_state(
+    hass: HomeAssistant,
+    mock_client: APIClient,
+    mock_generic_device_entry,
+) -> None:
+    """Test a generic date entity with missing state."""
+    entity_info = [
+        DateInfo(
+            object_id="mydate",
+            key=1,
+            name="my date",
+            unique_id="my_date",
+        )
+    ]
+    states = [DateState(key=1, missing_state=True)]
+    user_service = []
+    await mock_generic_device_entry(
+        mock_client=mock_client,
+        entity_info=entity_info,
+        user_service=user_service,
+        states=states,
+    )
+    state = hass.states.get("date.test_mydate")
+    assert state is not None
+    assert state.state == STATE_UNKNOWN