libretro/tests/test_torrentzip.py

"""Tests for the TorrentZip builder against real MAME romsets."""
from __future__ import annotations

import hashlib
import os
import sys
import tempfile
import unittest
import zipfile

REPO_ROOT = os.path.join(os.path.dirname(__file__), "..")
sys.path.insert(0, os.path.join(REPO_ROOT, "scripts"))

from torrentzip import (  # noqa: E402
    build_torrentzip,
    identify_romset,
    is_torrentzip,
    rebuild_torrentzip,
)


class TorrentZipTest(unittest.TestCase):
    """The format is deterministic: same members always give the same bytes."""

    def test_deterministic_output(self):
        members = [("b.rom", b"second"), ("a.rom", b"first")]
        self.assertEqual(build_torrentzip(members), build_torrentzip(members))

    def test_member_order_is_irrelevant(self):
        a = build_torrentzip([("a.rom", b"one"), ("b.rom", b"two")])
        b = build_torrentzip([("b.rom", b"two"), ("a.rom", b"one")])
        self.assertEqual(a, b)

    def test_case_insensitive_sorting(self):
        data = build_torrentzip([("B.rom", b"x"), ("a.rom", b"y")])
        with zipfile.ZipFile(_as_file(self, data)) as zf:
            self.assertEqual([i.filename for i in zf.infolist()], ["a.rom", "B.rom"])

    def test_fixed_timestamp_and_signature(self):
        data = build_torrentzip([("a.rom", b"payload")])
        with zipfile.ZipFile(_as_file(self, data)) as zf:
            self.assertEqual(zf.infolist()[0].date_time, (1996, 12, 24, 23, 32, 0))
            self.assertTrue(zf.comment.decode().startswith("TORRENTZIPPED-"))

    def test_roundtrip_readable_content(self):
        data = build_torrentzip([("a.rom", b"hello"), ("b.rom", b"world")])
        with zipfile.ZipFile(_as_file(self, data)) as zf:
            self.assertEqual(zf.read("a.rom"), b"hello")
            self.assertEqual(zf.read("b.rom"), b"world")

    def test_rebuild_matches_real_mame_set(self):
        """Rebuilding a shipped MAME romset reproduces it byte for byte."""
        candidates = [
            os.path.join(REPO_ROOT, "bios", "Arcade", "Arcade", "naomi2.zip"),
            os.path.join(REPO_ROOT, "bios", "Arcade", "MAME", "naomi2.zip"),
        ]
        checked = 0
        for path in candidates:
            if not os.path.exists(path) or not is_torrentzip(path):
                continue
            with open(path, "rb") as fh:
                original = fh.read()
            self.assertEqual(rebuild_torrentzip(path), original, path)
            checked += 1
        if not checked:
            self.skipTest("no TorrentZip romset available")

    def test_source_renamed_sets_stay_reproducible(self):
        """Archives whose member names we corrected must rebuild identically.

        Renaming a ROM by hand produced archives that matched no upstream set
        and could not be regenerated from their contents either. The corrected
        primaries carry the MAME 0.289 names and TorrentZip bytes, so anyone
        holding the ROMs reproduces them exactly.
        """
        corrected = [
            os.path.join(REPO_ROOT, "bios", "Arcade", "MAME", "manager.zip"),
            os.path.join(REPO_ROOT, "bios", "Arcade", "Arcade", "sys573.zip"),
            os.path.join(REPO_ROOT, "bios", "Arcade", "Arcade", "cedmag.zip"),
            os.path.join(
                REPO_ROOT, "bios", "Entex", "Adventure Vision", "advision.zip"
            ),
        ]
        checked = 0
        for path in corrected:
            if not os.path.exists(path):
                continue
            self.assertTrue(is_torrentzip(path), path)
            with open(path, "rb") as fh:
                original = fh.read()
            self.assertEqual(rebuild_torrentzip(path), original, path)
            checked += 1
        if not checked:
            self.skipTest("corrected romsets not present in this checkout")

    def test_source_renamed_sets_carry_the_source_names(self):
        """The member names come from MAME, not from a YAML round-trip."""
        expected = {
            os.path.join(REPO_ROOT, "bios", "Arcade", "MAME", "manager.zip"): {
                "01", "23",
            },
            os.path.join(
                REPO_ROOT, "bios", "Entex", "Adventure Vision", "advision.zip"
            ): {"ins8048-11kdp_n.u5", "cop411l-kcn_n.u8"},
        }
        checked = 0
        for path, names in expected.items():
            if not os.path.exists(path):
                continue
            with zipfile.ZipFile(path) as archive:
                members = {
                    info.filename
                    for info in archive.infolist()
                    if not info.is_dir()
                }
            self.assertEqual(members, names, path)
            checked += 1
        if not checked:
            self.skipTest("corrected romsets not present in this checkout")

    def test_identify_romset_selects_matching_recipe(self):
        atoms = {"3610a686": b"alpha", "9d0d1b46": b"beta"}
        import zlib

        atoms = {
            f"{zlib.crc32(b'alpha') & 0xffffffff:08x}": b"alpha",
            f"{zlib.crc32(b'beta') & 0xffffffff:08x}": b"beta",
        }
        crc_a, crc_b = list(atoms)
        wanted = hashlib.md5(
            build_torrentzip([("a.rom", b"alpha"), ("b.rom", b"beta")])
        ).hexdigest()
        recipes = {
            "v1": [("a.rom", crc_a)],
            "v2": [("a.rom", crc_a), ("b.rom", crc_b)],
        }
        self.assertEqual(identify_romset(recipes, atoms, wanted), "v2")
        self.assertIsNone(identify_romset(recipes, atoms, "0" * 32))

    def test_identify_romset_skips_recipes_with_absent_atoms(self):
        atoms = {"aaaaaaaa": b"x"}
        recipes = {"v1": [("a.rom", "ffffffff")]}
        self.assertIsNone(identify_romset(recipes, atoms, "0" * 32))


def _as_file(test: unittest.TestCase, data: bytes) -> str:
    """Write bytes to a temp file cleaned up with the test."""
    fd, path = tempfile.mkstemp(suffix=".zip")
    os.close(fd)
    with open(path, "wb") as fh:
        fh.write(data)
    test.addCleanup(os.unlink, path)
    return path


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