neser 0.1.1

NESER - NES Emulator in Rust - is a NES emulator written in Rust. It aims to be a high-quality, hardware-accurate emulator that is also easy to use and extend. It supports a wide range of NES games and features, including various mappers, audio processing, and input handling. NESER is designed to be modular and extensible, allowing developers to easily add new features or support for additional hardware. It can be run using one of two frontends: a native desktop application using SDL2, or a web application using WebAssembly. The desktop application provides a high-performance, feature-rich experience with support for various input devices and display options, while the web application allows users to play NES games directly in their browsers without needing to install any software in a BYOR manner (Bring Your Own Roms).
Documentation 
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"""Unit tests for RomFileDatabase scanning and persistence."""

from pathlib import Path
import tempfile
import unittest

from .rom_db_index import RomDbIndex
from .rom_file_database import RomFileDatabase
from .test_helpers import crc_from_rom_bytes, make_ines_rom


class RomFileDatabaseTests(unittest.TestCase):
    """Behavior tests for scan/update and invalid handling."""

    def test_scan_persists_new_rom_records(self) -> None:
        """Scan appends discovered ROMs and writes rom_files.csv."""

        with tempfile.TemporaryDirectory() as temp_dir_str:
            temp_root = Path(temp_dir_str)
            rom_root = temp_root / "roms"
            rom_root.mkdir(parents=True)
            (rom_root / "sample.nes").write_bytes(make_ines_rom(mapper=2, submapper=1))

            rom_files_db_path = temp_root / "rom_files.csv"
            db = RomFileDatabase(rom_files_db_path)

            records, new_records, updated_records, invalid_marked, warnings, was_cancelled = db.scan_and_update(
                rom_root,
                RomDbIndex({}),
            )

            self.assertTrue(rom_files_db_path.exists())
            self.assertIn("sample.nes", records)
            self.assertEqual(len(new_records), 1)
            self.assertEqual(updated_records, 0)
            self.assertEqual(invalid_marked, 0)
            self.assertEqual(warnings, [])
            self.assertFalse(was_cancelled)

    def test_scan_applies_rom_db_override_to_new_record(self) -> None:
        """Scan uses rom_db.csv CRC override for mapper/submapper values."""

        with tempfile.TemporaryDirectory() as temp_dir_str:
            temp_root = Path(temp_dir_str)
            rom_root = temp_root / "roms"
            rom_root.mkdir(parents=True)
            rom_bytes = make_ines_rom(mapper=1, submapper=None, fill_prg=0x12, fill_chr=0x34)
            (rom_root / "override-me.nes").write_bytes(rom_bytes)

            crc = crc_from_rom_bytes(rom_bytes)
            rom_db_path = temp_root / "rom_db.csv"
            rom_db_path.write_text(
                f"1,Override Test,,{crc},0,Licensed Japan,66,3,H,0,0,0,0,0,0,0,0,0,,,1\n",
                encoding="utf-8",
            )

            db = RomFileDatabase(temp_root / "rom_files.csv")
            index = RomDbIndex.from_csv(rom_db_path)
            records, *_ = db.scan_and_update(rom_root, index)

            record = records.get("override-me.nes")
            self.assertIsNotNone(record)
            assert record is not None
            self.assertEqual(record.mapper, "66")
            self.assertEqual(record.submapper, "3")
            self.assertEqual(record.mapper_source, "rom_db_override")

    def test_scan_marks_record_when_corresponding_autorun_file_exists(self) -> None:
        """Scan marks records with existing sibling .autorun files."""

        with tempfile.TemporaryDirectory() as temp_dir_str:
            temp_root = Path(temp_dir_str)
            rom_root = temp_root / "roms"
            rom_root.mkdir(parents=True)

            (rom_root / "sample.nes").write_bytes(make_ines_rom(mapper=2, submapper=1))
            (rom_root / "sample.autorun").write_text("{}", encoding="utf-8")

            db = RomFileDatabase(temp_root / "rom_files.csv")
            records, *_ = db.scan_and_update(rom_root, RomDbIndex({}))

            record = records.get("sample.nes")
            self.assertIsNotNone(record)
            assert record is not None
            self.assertTrue(record.has_autorun)
            self.assertEqual(record.autorun_status, "not_run")

    def test_scan_reconciles_existing_row_to_override(self) -> None:
        """Existing rows are updated when rom_db overrides become available."""

        with tempfile.TemporaryDirectory() as temp_dir_str:
            temp_root = Path(temp_dir_str)
            rom_root = temp_root / "roms"
            rom_root.mkdir(parents=True)
            rom_bytes = make_ines_rom(mapper=1, submapper=None, fill_prg=0x12, fill_chr=0x34)
            (rom_root / "existing.nes").write_bytes(rom_bytes)

            crc = crc_from_rom_bytes(rom_bytes)
            rom_db_path = temp_root / "rom_db.csv"
            rom_db_path.write_text(
                f"1,Override Existing,,{crc},0,Licensed Japan,9,4,H,0,0,0,0,0,0,0,0,0,,,1\n",
                encoding="utf-8",
            )

            rom_files_db_path = temp_root / "rom_files.csv"
            rom_files_db_path.write_text(
                "rom_path,crc,header_mapper,header_submapper,mapper,submapper,mapper_source\n"
                f"existing.nes,{crc},1,,1,,header\n",
                encoding="utf-8",
            )

            db = RomFileDatabase(rom_files_db_path)
            index = RomDbIndex.from_csv(rom_db_path)
            records, new_records, updated_records, invalid_marked, warnings, was_cancelled = db.scan_and_update(
                rom_root,
                index,
            )

            record = records.get("existing.nes")
            self.assertIsNotNone(record)
            assert record is not None
            self.assertEqual(record.mapper, "9")
            self.assertEqual(record.submapper, "4")
            self.assertEqual(record.mapper_source, "rom_db_override")
            self.assertEqual(record.autorun_status, "na")
            self.assertEqual(len(new_records), 0)
            self.assertEqual(updated_records, 1)
            self.assertEqual(invalid_marked, 0)
            self.assertEqual(warnings, [])
            self.assertFalse(was_cancelled)

    def test_load_legacy_rows_default_autorun_status_from_has_autorun(self) -> None:
        """Legacy CSV rows without autorun_status get sane defaults when loaded."""

        with tempfile.TemporaryDirectory() as temp_dir_str:
            temp_root = Path(temp_dir_str)
            db_path = temp_root / "rom_files.csv"
            db_path.write_text(
                "rom_path,crc,header_mapper,header_submapper,mapper,submapper,mapper_source,has_autorun,is_valid,parse_error\n"
                "with_autorun.nes,AAAA0001,1,,1,,header,1,1,\n"
                "without_autorun.nes,BBBB0002,1,,1,,header,0,1,\n",
                encoding="utf-8",
            )

            records = RomFileDatabase(db_path).load()

            self.assertEqual(records["with_autorun.nes"].autorun_status, "not_run")
            self.assertEqual(records["without_autorun.nes"].autorun_status, "na")

    def test_invalid_rom_is_persisted_and_skipped_on_next_scan(self) -> None:
        """Invalid ROMs are stored as invalid entries and not reparsed later."""

        with tempfile.TemporaryDirectory() as temp_dir_str:
            temp_root = Path(temp_dir_str)
            rom_root = temp_root / "roms"
            rom_root.mkdir(parents=True)
            (rom_root / "broken.nes").write_bytes(b"not-a-valid-ines")

            db = RomFileDatabase(temp_root / "rom_files.csv")
            records_first, _, _, invalid_marked_first, warnings_first, cancelled_first = db.scan_and_update(
                rom_root,
                RomDbIndex({}),
            )

            first_record = records_first.get("broken.nes")
            self.assertIsNotNone(first_record)
            assert first_record is not None
            self.assertFalse(first_record.is_valid)
            self.assertEqual(first_record.mapper_source, "invalid")
            self.assertEqual(invalid_marked_first, 1)
            self.assertTrue(any("Marked invalid ROM" in warning for warning in warnings_first))
            self.assertFalse(cancelled_first)

            records_second, _, updated_second, invalid_marked_second, warnings_second, cancelled_second = db.scan_and_update(
                rom_root,
                RomDbIndex({}),
            )
            second_record = records_second.get("broken.nes")
            self.assertIsNotNone(second_record)
            assert second_record is not None
            self.assertFalse(second_record.is_valid)
            self.assertEqual(updated_second, 0)
            self.assertEqual(invalid_marked_second, 0)
            self.assertEqual(warnings_second, [])
            self.assertFalse(cancelled_second)

    def test_scan_honors_cancellation_callback(self) -> None:
        """Scan stops early and reports cancellation when callback requests it."""

        with tempfile.TemporaryDirectory() as temp_dir_str:
            temp_root = Path(temp_dir_str)
            rom_root = temp_root / "roms"
            rom_root.mkdir(parents=True)
            (rom_root / "a.nes").write_bytes(make_ines_rom(mapper=1, submapper=0))
            (rom_root / "b.nes").write_bytes(make_ines_rom(mapper=2, submapper=0))

            db = RomFileDatabase(temp_root / "rom_files.csv")

            call_count = 0

            def should_cancel() -> bool:
                nonlocal call_count
                call_count += 1
                return call_count >= 2

            records, _, _, _, _, was_cancelled = db.scan_and_update(
                rom_root,
                RomDbIndex({}),
                should_cancel=should_cancel,
            )

            self.assertTrue(was_cancelled)
            self.assertLessEqual(len(records), 1)