Cover the tidy-project idedata assembly and hoist its helper import

esphome/espidf/clang_tidy.py

@@ -23,6 +23,8 @@ from dataclasses import dataclass
 import os
 from pathlib import Path
 
+from esphome.build_helpers.idedata import _get_toolchain_includes, _parse_entry
+
 TIDY_PROJECT_NAME = "esphome_tidy"
 
 # A do-nothing C++ app: just enough for IDF to configure a valid project. It's
@@ -415,8 +417,6 @@ def _idedata_from_tidy_project(compile_commands: Path) -> dict:
     """
     import json
 
-    from esphome.build_helpers.idedata import _get_toolchain_includes, _parse_entry
-
     entries = json.loads(Path(compile_commands).read_text(encoding="utf-8"))
     entry = next((e for e in entries if e["file"].endswith("tidy.cpp")), None)
     if entry is None:

tests/unit_tests/test_espidf_clang_tidy.py

@@ -64,3 +64,44 @@ def test_setup_core_sets_arduino_env(
     _setup_core(tmp_path / "proj", _settings(target_framework=target_framework))
 
     assert os.environ["ESPHOME_ARDUINO_COMPONENT"] == expected
+
+
+def test_idedata_from_tidy_project(tmp_path) -> None:
+    """The tidy TU's compile entry is assembled into consumer-shaped idedata."""
+    import json
+    from unittest.mock import patch
+
+    from esphome.espidf import clang_tidy
+
+    compile_commands = tmp_path / "compile_commands.json"
+    compile_commands.write_text(
+        json.dumps(
+            [
+                {
+                    "directory": str(tmp_path),
+                    "file": str(tmp_path / "main" / "tidy.cpp"),
+                    "command": "/tc/xtensa-esp32-elf-g++ -DUSE_ESP32 "
+                    f"-I{tmp_path}/inc -c main/tidy.cpp -o tidy.o",
+                }
+            ]
+        )
+    )
+    with patch(
+        "esphome.espidf.clang_tidy._get_toolchain_includes", return_value=["/tc/inc"]
+    ):
+        data = clang_tidy._idedata_from_tidy_project(compile_commands)
+    assert data["cxx_path"] == "/tc/xtensa-esp32-elf-g++"
+    assert data["defines"] == ["USE_ESP32"]
+    assert data["includes"]["toolchain"] == ["/tc/inc"]
+    assert any(inc.endswith("/inc") for inc in data["includes"]["build"])
+
+
+def test_idedata_from_tidy_project_missing_tu_raises(tmp_path) -> None:
+    import json
+
+    from esphome.espidf import clang_tidy
+
+    compile_commands = tmp_path / "compile_commands.json"
+    compile_commands.write_text(json.dumps([]))
+    with pytest.raises(RuntimeError, match="tidy.cpp not found"):
+        clang_tidy._idedata_from_tidy_project(compile_commands)