[core] cpp tests: Allow customizing code generation during tests (#14681)

Co-authored-by: J. Nick Koston <nick@home-assistant.io>
Co-authored-by: J. Nick Koston <nick@koston.org>

tests/script/test_determine_jobs.py

@@ -1846,7 +1846,7 @@ def test_should_run_benchmarks_benchmark_infra_change() -> None:
     """Test benchmarks trigger on benchmark infrastructure changes."""
     for infra_file in [
         "script/cpp_benchmark.py",
-        "script/test_helpers.py",
+        "script/build_helpers.py",
         "script/setup_codspeed_lib.py",
     ]:
         with patch.object(determine_jobs, "changed_files", return_value=[infra_file]):

tests/script/test_helpers.py

@@ -1073,28 +1073,6 @@ def test_get_all_dependencies_platform_component_with_dependencies() -> None:
         assert result == {"sensor.bthome", "sensor"}
 
 
-def test_get_all_dependencies_cpp_testing_flag() -> None:
-    """cpp_testing=True propagates to CORE.cpp_testing during resolution."""
-    from esphome.core import CORE
-
-    with (
-        patch("esphome.loader.get_component") as mock_get_component,
-        patch("esphome.loader.get_platform"),
-    ):
-        observed: list[bool] = []
-
-        def capturing_get_component(name: str):
-            observed.append(CORE.cpp_testing)
-
-        mock_get_component.side_effect = capturing_get_component
-
-        helpers.get_all_dependencies({"some_comp"}, cpp_testing=True)
-
-    assert observed and all(observed), (
-        "CORE.cpp_testing should be True during resolution"
-    )
-
-
 def test_get_components_from_integration_fixtures() -> None:
     """Test extraction of components from fixture YAML files."""
     yaml_content = {

tests/script/test_test_helpers.py

@@ -0,0 +1,260 @@
+"""Unit tests for script/build_helpers.py manifest override and build helpers."""
+
+import os
+from pathlib import Path
+import sys
+import textwrap
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+# Add the script directory to Python path so we can import build_helpers
+sys.path.insert(
+    0, os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "..", "script"))
+)
+
+import build_helpers  # noqa: E402
+
+from esphome.loader import ComponentManifest  # noqa: E402
+from tests.testing_helpers import ComponentManifestOverride  # noqa: E402
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+
+def _make_component_manifest(*, to_code=None, dependencies=None) -> ComponentManifest:
+    mod = MagicMock()
+    mod.to_code = to_code
+    mod.DEPENDENCIES = dependencies or []
+    return ComponentManifest(mod)
+
+
+# ---------------------------------------------------------------------------
+# filter_components_with_files
+# ---------------------------------------------------------------------------
+
+
+def test_filter_keeps_components_with_cpp_files(tmp_path: Path) -> None:
+    comp_dir = tmp_path / "mycomp"
+    comp_dir.mkdir()
+    (comp_dir / "mycomp_test.cpp").write_text("")
+
+    result = build_helpers.filter_components_with_files(["mycomp"], tmp_path)
+
+    assert result == ["mycomp"]
+
+
+def test_filter_keeps_components_with_h_files(tmp_path: Path) -> None:
+    comp_dir = tmp_path / "mycomp"
+    comp_dir.mkdir()
+    (comp_dir / "helpers.h").write_text("")
+
+    result = build_helpers.filter_components_with_files(["mycomp"], tmp_path)
+
+    assert result == ["mycomp"]
+
+
+def test_filter_drops_components_without_test_dir(tmp_path: Path) -> None:
+    result = build_helpers.filter_components_with_files(["nodir"], tmp_path)
+
+    assert result == []
+
+
+def test_filter_drops_components_with_no_cpp_or_h(tmp_path: Path) -> None:
+    comp_dir = tmp_path / "mycomp"
+    comp_dir.mkdir()
+    (comp_dir / "README.md").write_text("")
+
+    result = build_helpers.filter_components_with_files(["mycomp"], tmp_path)
+
+    assert result == []
+
+
+# ---------------------------------------------------------------------------
+# get_platform_components
+# ---------------------------------------------------------------------------
+
+
+def test_get_platform_components_discovers_subdirectory(tmp_path: Path) -> None:
+    (tmp_path / "bthome" / "sensor").mkdir(parents=True)
+
+    sensor_mod = MagicMock()
+    sensor_mod.IS_PLATFORM_COMPONENT = True
+
+    with patch(
+        "build_helpers.get_component", return_value=ComponentManifest(sensor_mod)
+    ):
+        result = build_helpers.get_platform_components(["bthome"], tmp_path)
+
+    assert result == ["sensor.bthome"]
+
+
+def test_get_platform_components_skips_pycache(tmp_path: Path) -> None:
+    (tmp_path / "bthome" / "__pycache__").mkdir(parents=True)
+
+    result = build_helpers.get_platform_components(["bthome"], tmp_path)
+
+    assert result == []
+
+
+def test_get_platform_components_raises_for_invalid_domain(tmp_path: Path) -> None:
+    (tmp_path / "bthome" / "notadomain").mkdir(parents=True)
+
+    with (
+        patch("build_helpers.get_component", return_value=None),
+        pytest.raises(ValueError, match="notadomain"),
+    ):
+        build_helpers.get_platform_components(["bthome"], tmp_path)
+
+
+# ---------------------------------------------------------------------------
+# load_test_manifest_overrides
+# ---------------------------------------------------------------------------
+
+
+def test_load_suppresses_to_code(tmp_path: Path) -> None:
+    """to_code is always set to None before the override is called."""
+
+    async def real_to_code(config):
+        pass
+
+    inner = _make_component_manifest(to_code=real_to_code)
+
+    with (
+        patch("build_helpers.get_component", return_value=inner),
+        patch("build_helpers.set_testing_manifest") as mock_set,
+    ):
+        build_helpers.load_test_manifest_overrides(["mycomp"], tmp_path)
+        installed: ComponentManifestOverride = mock_set.call_args[0][1]
+
+    assert installed.to_code is None
+
+
+def test_load_calls_override_fn(tmp_path: Path) -> None:
+    """override_manifest() in test_init is called with the ComponentManifestOverride."""
+    comp_dir = tmp_path / "mycomp"
+    comp_dir.mkdir()
+    init_py = comp_dir / "__init__.py"
+    init_py.write_text(
+        textwrap.dedent("""\
+        def override_manifest(manifest):
+            manifest.dependencies = ["injected"]
+    """)
+    )
+
+    inner = _make_component_manifest()
+    override = ComponentManifestOverride(inner)
+    override.to_code = None
+
+    with (
+        patch("build_helpers.get_component", return_value=inner),
+        patch("build_helpers.set_testing_manifest") as mock_set,
+    ):
+        build_helpers.load_test_manifest_overrides(["mycomp"], tmp_path)
+        installed: ComponentManifestOverride = mock_set.call_args[0][1]
+
+    assert installed.dependencies == ["injected"]
+
+
+def test_load_enable_codegen_in_override(tmp_path: Path) -> None:
+    """An override_manifest that calls enable_codegen() restores to_code."""
+
+    async def real_to_code(config):
+        pass
+
+    comp_dir = tmp_path / "mycomp"
+    comp_dir.mkdir()
+    init_py = comp_dir / "__init__.py"
+    init_py.write_text(
+        textwrap.dedent("""\
+        def override_manifest(manifest):
+            manifest.enable_codegen()
+    """)
+    )
+
+    inner = _make_component_manifest(to_code=real_to_code)
+
+    with (
+        patch("build_helpers.get_component", return_value=inner),
+        patch("build_helpers.set_testing_manifest") as mock_set,
+    ):
+        build_helpers.load_test_manifest_overrides(["mycomp"], tmp_path)
+        installed: ComponentManifestOverride = mock_set.call_args[0][1]
+
+    assert installed.to_code is real_to_code
+
+
+def test_load_no_override_file(tmp_path: Path) -> None:
+    """No override file: manifest is wrapped and to_code suppressed, nothing else."""
+    inner = _make_component_manifest()
+
+    with (
+        patch("build_helpers.get_component", return_value=inner),
+        patch("build_helpers.set_testing_manifest") as mock_set,
+    ):
+        build_helpers.load_test_manifest_overrides(["mycomp"], tmp_path)
+
+    mock_set.assert_called_once()
+    key, installed = mock_set.call_args[0]
+    assert key == "mycomp"
+    assert isinstance(installed, ComponentManifestOverride)
+
+
+def test_load_skips_already_wrapped(tmp_path: Path) -> None:
+    """Components already wrapped as ComponentManifestOverride are not double-wrapped."""
+    inner = _make_component_manifest()
+    already_wrapped = ComponentManifestOverride(inner)
+
+    with (
+        patch("build_helpers.get_component", return_value=already_wrapped),
+        patch("build_helpers.set_testing_manifest") as mock_set,
+    ):
+        build_helpers.load_test_manifest_overrides(["mycomp"], tmp_path)
+
+    mock_set.assert_not_called()
+
+
+def test_load_skips_platform_component_already_wrapped(tmp_path: Path) -> None:
+    inner = _make_component_manifest()
+    already_wrapped = ComponentManifestOverride(inner)
+
+    with (
+        patch("build_helpers.get_platform", return_value=already_wrapped),
+        patch("build_helpers.set_testing_manifest") as mock_set,
+    ):
+        build_helpers.load_test_manifest_overrides(["sensor.bthome"], tmp_path)
+
+    mock_set.assert_not_called()
+
+
+def test_load_wraps_top_level_component(tmp_path: Path) -> None:
+    inner = _make_component_manifest()
+
+    with (
+        patch("build_helpers.get_component", return_value=inner),
+        patch("build_helpers.set_testing_manifest") as mock_set,
+    ):
+        build_helpers.load_test_manifest_overrides(["mycomp"], tmp_path)
+
+    mock_set.assert_called_once()
+    key, installed = mock_set.call_args[0]
+    assert key == "mycomp"
+    assert isinstance(installed, ComponentManifestOverride)
+    assert installed.to_code is None
+
+
+def test_load_wraps_platform_component(tmp_path: Path) -> None:
+    inner = _make_component_manifest()
+
+    with (
+        patch("build_helpers.get_platform", return_value=inner),
+        patch("build_helpers.set_testing_manifest") as mock_set,
+    ):
+        build_helpers.load_test_manifest_overrides(["sensor.bthome"], tmp_path)
+
+    mock_set.assert_called_once()
+    key, installed = mock_set.call_args[0]
+    assert key == "bthome.sensor"
+    assert isinstance(installed, ComponentManifestOverride)
+    assert installed.to_code is None