Add direct tests for the shared pch helpers

tests/unit_tests/build_helpers/test_ccache.py

@@ -10,6 +10,7 @@ from unittest.mock import patch
 import pytest
 
 from esphome.build_helpers import ccache
+from esphome.core import CORE
 
 
 def test_resolve_opt_out() -> None:
@@ -120,3 +121,11 @@ def test_parse_enable_env_spelling_tables(
     """cv.boolean's spelling tables plus the 1/0 env convention."""
     monkeypatch.setenv("ESPHOME_CCACHE_ENABLE", raw)
     assert ccache.parse_enable_env("ESPHOME_CCACHE_ENABLE") is expected
+
+
+def test_effective_ccache_basedir_prefers_user_value(tmp_path: Path) -> None:
+    CORE.build_path = tmp_path
+    with patch.dict(os.environ, {"CCACHE_BASEDIR": "/custom/base"}, clear=True):
+        assert ccache.effective_ccache_basedir() == "/custom/base"
+    with patch.dict(os.environ, {}, clear=True):
+        assert ccache.effective_ccache_basedir() == str(tmp_path.resolve())

tests/unit_tests/build_helpers/test_pch.py

@@ -0,0 +1,116 @@
+"""Tests for esphome.build_helpers.pch."""
+
+from __future__ import annotations
+
+import os
+from pathlib import Path
+from unittest.mock import patch
+
+import pytest
+
+from esphome.build_helpers import pch
+
+
+def _write(src_dir: Path, name: str, content: str) -> None:
+    path = src_dir / name
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_text(content)
+
+
+@pytest.mark.parametrize(
+    ("value", "expected"),
+    [
+        (None, True),
+        ("1", True),
+        ("0", False),
+        ("false", False),
+        ("", False),
+    ],
+)
+def test_pch_enabled(value: str | None, expected: bool) -> None:
+    env = {} if value is None else {"ESPHOME_PCH_ENABLE": value}
+    with patch.dict(os.environ, env, clear=True):
+        assert pch.pch_enabled() is expected
+
+
+def test_ccache_pch_env_enabled() -> None:
+    with patch.dict(os.environ, {}, clear=True):
+        env = pch.ccache_pch_env()
+    assert env["CCACHE_SLOPPINESS"] == "pch_defines,time_macros"
+    assert env["CCACHE_PCH_EXTSUM"] == "true"
+
+
+def test_ccache_pch_env_disabled() -> None:
+    with patch.dict(os.environ, {"ESPHOME_PCH_ENABLE": "0"}, clear=True):
+        assert pch.ccache_pch_env() == {}
+
+
+def test_ccache_pch_env_respects_user_values() -> None:
+    with patch.dict(os.environ, {"CCACHE_SLOPPINESS": "locale"}, clear=True):
+        env = pch.ccache_pch_env()
+    assert "CCACHE_SLOPPINESS" not in env
+    assert env["CCACHE_PCH_EXTSUM"] == "true"
+
+
+def test_pch_header_text_preserves_order() -> None:
+    text = pch.pch_header_text(["b.h", "a.h"])
+    assert text == '#include "b.h"\n#include "a.h"\n'
+
+
+def test_include_closure_resolves_relative_and_root(tmp_path: Path) -> None:
+    """Sibling includes resolve against the includer's directory first,
+    full paths against the src root; unresolvable names end the walk."""
+    _write(tmp_path, "esphome/components/x/a.h", '#include "b.h"\n')
+    _write(
+        tmp_path,
+        "esphome/components/x/b.h",
+        '#include "esphome/core/deep.h"\n#include <system.h>\n#include "missing.h"\n',
+    )
+    _write(tmp_path, "esphome/core/deep.h", "")
+    closure = pch._include_closure(tmp_path, ["esphome/components/x/a.h"])
+    assert sorted(closure) == [
+        "esphome/components/x/a.h",
+        "esphome/components/x/b.h",
+        "esphome/core/deep.h",
+    ]
+
+
+def test_include_closure_handles_cycles(tmp_path: Path) -> None:
+    _write(tmp_path, "a.h", '#include "b.h"\n')
+    _write(tmp_path, "b.h", '#include "a.h"\n')
+    assert sorted(pch._include_closure(tmp_path, ["a.h"])) == ["a.h", "b.h"]
+
+
+def test_include_closure_blocks_parent_escape(tmp_path: Path) -> None:
+    _write(tmp_path / "src", "a.h", '#include "../outside.h"\n')
+    (tmp_path / "outside.h").write_text("")
+    assert sorted(pch._include_closure(tmp_path / "src", ["a.h"])) == ["a.h"]
+
+
+def test_pch_checksum_tracks_closure_content(tmp_path: Path) -> None:
+    """A transitive header edit or an extra-identity change must change the
+    digest; unrelated files must not."""
+    _write(tmp_path, "root.h", '#include "nested.h"\n')
+    _write(tmp_path, "nested.h", "int a;\n")
+    _write(tmp_path, "unrelated.h", "int u;\n")
+    base = pch.pch_checksum(tmp_path, ["root.h"], ["id"])
+    assert base == pch.pch_checksum(tmp_path, ["root.h"], ["id"])
+    assert base != pch.pch_checksum(tmp_path, ["root.h"], ["other-id"])
+    _write(tmp_path, "unrelated.h", "int changed;\n")
+    assert base == pch.pch_checksum(tmp_path, ["root.h"], ["id"])
+    _write(tmp_path, "nested.h", "int b;\n")
+    assert base != pch.pch_checksum(tmp_path, ["root.h"], ["id"])
+
+
+@pytest.mark.skipif(
+    os.name == "nt" or os.geteuid() == 0, reason="chmod is ineffective here"
+)
+def test_include_closure_skips_unreadable(tmp_path: Path) -> None:
+    _write(tmp_path, "a.h", '#include "locked.h"\n')
+    locked = tmp_path / "locked.h"
+    locked.write_text("")
+    locked.chmod(0)
+    try:
+        assert sorted(pch._include_closure(tmp_path, ["a.h"])) == ["a.h"]
+    finally:
+        locked.chmod(0o644)