[lvgl] Build automation_schema event validators lazily (#16633)

tests/component_tests/lvgl/test_automation_schema_lazy.py

@@ -0,0 +1,71 @@
+"""Tests for lvgl automation_schema lazy validate_automation build."""
+
+from __future__ import annotations
+
+from unittest.mock import patch
+
+import esphome.components.lvgl  # noqa: F401
+from esphome.components.lvgl import schemas as lvgl_schemas
+from esphome.components.lvgl.schemas import (
+    WIDGET_TYPES,
+    _lazy_validate_automation,
+    automation_schema,
+)
+from esphome.components.lvgl.widgets import WidgetType
+from esphome.config_validation import GenerateID, declare_id
+from esphome.const import CONF_TRIGGER_ID
+from esphome.core.config import StartupTrigger
+
+
+def _widget_type(name: str = "obj") -> WidgetType:
+    wt = WIDGET_TYPES.get(name)
+    assert wt is not None, f"widget type {name!r} not registered"
+    return wt
+
+
+def _trigger_extra_schema() -> dict:
+    return {GenerateID(CONF_TRIGGER_ID): declare_id(StartupTrigger)}
+
+
+def test_lazy_validator_defers_build_until_first_call() -> None:
+    with patch(
+        "esphome.components.lvgl.schemas.validate_automation",
+        wraps=lvgl_schemas.validate_automation,
+    ) as va_mock:
+        validator = _lazy_validate_automation(_trigger_extra_schema())
+        assert va_mock.call_count == 0
+        validator({"then": []})
+        assert va_mock.call_count == 1
+        validator({"then": []})
+        assert va_mock.call_count == 1
+
+
+def test_eager_build_when_schema_extraction_enabled() -> None:
+    with (
+        patch("esphome.components.lvgl.schemas.EnableSchemaExtraction", True),
+        patch(
+            "esphome.components.lvgl.schemas.validate_automation",
+            wraps=lvgl_schemas.validate_automation,
+        ) as va_mock,
+    ):
+        _lazy_validate_automation(_trigger_extra_schema())
+        assert va_mock.call_count == 1
+
+
+def test_lazy_and_eager_produce_equivalent_validation() -> None:
+    extra = _trigger_extra_schema()
+    with patch("esphome.components.lvgl.schemas.EnableSchemaExtraction", True):
+        eager = _lazy_validate_automation(extra)
+    lazy = _lazy_validate_automation(_trigger_extra_schema())
+    sample = {"then": []}
+    assert lazy(sample) == eager(sample)
+
+
+def test_automation_schema_uses_lazy_validators() -> None:
+    wt = _widget_type("obj")
+    with patch(
+        "esphome.components.lvgl.schemas.validate_automation",
+        wraps=lvgl_schemas.validate_automation,
+    ) as va_mock:
+        automation_schema(wt.w_type)
+        assert va_mock.call_count == 0