[automation] Eliminate trigger trampolines with deduplicated forwarder structs (#15174)

tests/unit_tests/test_automation.py

@@ -5,7 +5,13 @@ from unittest.mock import patch
 
 import pytest
 
-from esphome.automation import has_non_synchronous_actions
+from esphome.automation import (
+    TriggerForwarder,
+    TriggerOnFalseForwarder,
+    TriggerOnTrueForwarder,
+    has_non_synchronous_actions,
+)
+from esphome.cpp_generator import MockObj, RawExpression
 from esphome.util import RegistryEntry
 
 
@@ -175,3 +181,76 @@ def test_has_non_synchronous_actions_dict_input(
     """Direct dict input (single action)."""
     assert has_non_synchronous_actions({"delay": "1s"}) is True
     assert has_non_synchronous_actions({"logger.log": "hello"}) is False
+
+
+def _build_forwarder(
+    automation_name: str,
+    args: list[tuple[str, str]],
+    forwarder: MockObj | None = None,
+) -> str:
+    """Build a trigger forwarder expression the same way build_callback_automation does.
+
+    Mirrors the forwarder selection logic in automation.build_callback_automation.
+    """
+    import esphome.codegen as cg
+
+    obj = MockObj(automation_name, "->")
+    if forwarder is None:
+        arg_types = [RawExpression(t) for t, _ in args]
+        templ = (
+            cg.TemplateArguments(*arg_types) if arg_types else cg.TemplateArguments()
+        )
+        forwarder = TriggerForwarder.template(templ)
+    return f"{forwarder}{{{obj}}}"
+
+
+def test_trigger_forwarder_no_args() -> None:
+    """Button on_press: TriggerForwarder<> with no args."""
+    result = _build_forwarder("auto_1", [])
+    assert result == "TriggerForwarder<>{auto_1}"
+
+
+def test_trigger_forwarder_single_float_arg() -> None:
+    """Sensor on_value: TriggerForwarder<float>."""
+    result = _build_forwarder("auto_1", [("float", "x")])
+    assert result == "TriggerForwarder<float>{auto_1}"
+
+
+def test_trigger_forwarder_single_bool_arg() -> None:
+    """Switch on_state: TriggerForwarder<bool>."""
+    result = _build_forwarder("auto_1", [("bool", "x")])
+    assert result == "TriggerForwarder<bool>{auto_1}"
+
+
+def test_trigger_forwarder_on_true() -> None:
+    """Binary_sensor on_press / switch on_turn_on: TriggerOnTrueForwarder."""
+    result = _build_forwarder("auto_1", [], forwarder=TriggerOnTrueForwarder)
+    assert result == "TriggerOnTrueForwarder{auto_1}"
+
+
+def test_trigger_forwarder_on_false() -> None:
+    """Binary_sensor on_release / switch on_turn_off: TriggerOnFalseForwarder."""
+    result = _build_forwarder("auto_1", [], forwarder=TriggerOnFalseForwarder)
+    assert result == "TriggerOnFalseForwarder{auto_1}"
+
+
+def test_trigger_forwarder_multiple_args() -> None:
+    """Binary_sensor on_state_change: TriggerForwarder with two args."""
+    result = _build_forwarder(
+        "auto_1",
+        [("optional<bool>", "x_previous"), ("optional<bool>", "x")],
+    )
+    assert result == "TriggerForwarder<optional<bool>, optional<bool>>{auto_1}"
+
+
+def test_trigger_forwarder_string_arg() -> None:
+    """Text_sensor on_value: TriggerForwarder<std::string>."""
+    result = _build_forwarder("auto_1", [("std::string", "x")])
+    assert result == "TriggerForwarder<std::string>{auto_1}"
+
+
+def test_trigger_forwarder_custom_type() -> None:
+    """Custom forwarder type passed directly."""
+    custom = MockObj("MyForwarder", "")
+    result = _build_forwarder("auto_1", [], forwarder=custom)
+    assert result == "MyForwarder{auto_1}"