[core] Persist esphome.area in StorageJSON (#16710)

tests/unit_tests/core/test_config.py

@@ -140,6 +140,33 @@ def test_multiple_areas_and_devices(yaml_file: Callable[[str], str]) -> None:
     }
 
 
+@pytest.mark.asyncio
+@pytest.mark.filterwarnings("ignore::RuntimeWarning")
+@pytest.mark.parametrize(
+    ("fixture", "expected_area"),
+    [
+        ("legacy_string_area.yaml", "Living Room"),
+        ("multiple_areas_devices.yaml", "Main Area"),
+    ],
+)
+async def test_to_code_records_core_area(
+    yaml_file: Callable[[str], Path],
+    fixture: str,
+    expected_area: str,
+) -> None:
+    """``to_code`` records the node's area name on CORE for StorageJSON."""
+    result = load_config_from_fixture(yaml_file, fixture, FIXTURES_DIR)
+    assert result is not None
+    assert CORE.area is None
+
+    with patch("esphome.core.config.cg") as mock_cg:
+        mock_cg.RawStatement.side_effect = lambda *args, **kwargs: MagicMock()
+        mock_cg.RawExpression.side_effect = lambda *args, **kwargs: MagicMock()
+        await config.to_code(result[CONF_ESPHOME])
+
+    assert CORE.area == expected_area
+
+
 def test_legacy_string_area(
     yaml_file: Callable[[str], str], caplog: pytest.LogCaptureFixture
 ) -> None:

tests/unit_tests/test_storage_json.py

@@ -205,6 +205,7 @@ def test_storage_json_as_dict() -> None:
         no_mdns=True,
         framework="arduino",
         core_platform="esp32",
+        area="Living Room",
     )
 
     result = storage.as_dict()
@@ -233,6 +234,7 @@ def test_storage_json_as_dict() -> None:
     assert result["no_mdns"] is True
     assert result["framework"] == "arduino"
     assert result["core_platform"] == "esp32"
+    assert result["area"] == "Living Room"
 
 
 def test_storage_json_to_json() -> None:
@@ -309,6 +311,7 @@ def test_storage_json_from_esphome_core(setup_core: Path) -> None:
     mock_core.config = {CONF_MDNS: {CONF_DISABLED: True}}
     mock_core.target_framework = "esp-idf"
     mock_core.toolchain = Toolchain.ESP_IDF
+    mock_core.area = "Living Room"
 
     with patch("esphome.components.esp32.get_esp32_variant") as mock_variant:
         mock_variant.return_value = "ESP32-C3"
@@ -329,6 +332,7 @@ def test_storage_json_from_esphome_core(setup_core: Path) -> None:
     assert result.framework == "esp-idf"
     assert result.core_platform == "esp32"
     assert result.toolchain == "esp-idf"
+    assert result.area == "Living Room"
 
 
 def test_storage_json_from_esphome_core_mdns_enabled(setup_core: Path) -> None:
@@ -729,3 +733,37 @@ def test_storage_json_load_legacy_esphomeyaml_version(tmp_path: Path) -> None:
 
     assert result is not None
     assert result.esphome_version == "1.14.0"  # Should map to esphome_version
+
+
+def test_storage_json_load_area(tmp_path: Path) -> None:
+    """``area`` round-trips through load; absence loads as None."""
+    file_path = tmp_path / "with_area.json"
+    file_path.write_text(
+        json.dumps(
+            {
+                "storage_version": 1,
+                "name": "lamp",
+                "friendly_name": "Lamp",
+                "esp_platform": "ESP32",
+                "area": "Living Room",
+            }
+        )
+    )
+    result = storage_json.StorageJSON.load(file_path)
+    assert result is not None
+    assert result.area == "Living Room"
+
+    legacy_path = tmp_path / "no_area.json"
+    legacy_path.write_text(
+        json.dumps(
+            {
+                "storage_version": 1,
+                "name": "lamp",
+                "friendly_name": "Lamp",
+                "esp_platform": "ESP32",
+            }
+        )
+    )
+    legacy = storage_json.StorageJSON.load(legacy_path)
+    assert legacy is not None
+    assert legacy.area is None