"""Unit tests for writing the generated package-cache files.

The shape measured in a gate run: a container had rendered
compose/package-cache/pip.conf under its own uid, and the next host-side
render died on it with PermissionError while the directory stayed writable.
"""

from __future__ import annotations

import stat
import tempfile
import unittest
from pathlib import Path

from utils.cache.render import _write


class TestWrite(unittest.TestCase):
    """A file the renderer cannot overwrite is replaced, not given up on."""

    def test_an_unwritable_file_is_replaced(self) -> None:
        with tempfile.TemporaryDirectory() as directory:
            target = Path(directory, "pip.conf")
            target.write_text("stale", encoding="utf-8")
            target.chmod(stat.S_IRUSR | stat.S_IRGRP | stat.S_IROTH)

            _write(target, "fresh")

            self.assertEqual(
                target.read_text(
                    encoding="utf-8"
                ),  # nocheck: cache-read tempdir fixture rewritten in this test
                "fresh",
            )

    def test_a_writable_file_keeps_its_inode(self) -> None:
        with tempfile.TemporaryDirectory() as directory:
            target = Path(directory, "arch.list")
            target.write_text("stale", encoding="utf-8")
            before = target.stat().st_ino

            _write(target, "fresh")

            self.assertEqual(
                target.read_text(
                    encoding="utf-8"
                ),  # nocheck: cache-read tempdir fixture rewritten in this test
                "fresh",
            )
            self.assertEqual(target.stat().st_ino, before)

    def test_a_missing_parent_is_created(self) -> None:
        with tempfile.TemporaryDirectory() as directory:
            target = Path(directory, "apt", "debian.list")

            _write(target, "fresh")

            self.assertEqual(
                target.read_text(
                    encoding="utf-8"
                ),  # nocheck: cache-read tempdir fixture rewritten in this test
                "fresh",
            )


if __name__ == "__main__":
    unittest.main()