Refactor code style and improve documentation

- Standardized string quotes to single quotes across all files.
- Added docstrings to several functions and classes for better clarity.
- Updated mypy configuration in pyproject.toml for enhanced type checking.
- Ignored specific linting rules for test files in ruff configuration.
- Improved error messages in exception handling for better user feedback.
- Cleaned up code formatting and structure for consistency.

main.py

@@ -3,9 +3,9 @@ from __future__ import annotations
 import sys
 from pathlib import Path
 
-sys.path.insert(0, str(Path(__file__).resolve().parent / "src"))
+sys.path.insert(0, str(Path(__file__).resolve().parent / 'src'))
 
 from yt_shorts_downloader.cli import main
 
-if __name__ == "__main__":
+if __name__ == '__main__':
     raise SystemExit(main())

pyproject.toml

@@ -47,6 +47,9 @@ indent-style = "space"
 select = ["E", "F", "I", "UP", "B", "Q", "ERA", "D", "SIM", "ARG", "RUF", "C4", "RET", "ASYNC", "PERF", "PL"]
 ignore = ["D100", "RUF002", "D107", "RUF001", "D104", "D203", "D213", "ARG001"]
 
+[tool.ruff.lint.per-file-ignores]
+"tests/**/*.py" = ["D"]
+
 [tool.ruff.lint.flake8-quotes]
 inline-quotes = "single"
 multiline-quotes = "double"
@@ -55,11 +58,16 @@ avoid-escape = true
 
 
 [tool.mypy]
-python_version = "3.13"
+python_version = "3.12"
 strict = true
 warn_unused_ignores = true
 warn_redundant_casts = true
 warn_unreachable = true
+show_error_codes = true
+pretty = true
+explicit_package_bases = true
+files = ["src", "tests", "main.py"]
+mypy_path = "$MYPY_CONFIG_FILE_DIR/src:$MYPY_CONFIG_FILE_DIR/stubs"
 
 [tool.deptry.package_module_name_map]
 "yt-dlp" = "yt_dlp"

src/yt_shorts_downloader/__init__.py

@@ -11,16 +11,16 @@ from .exceptions import (
 from .models import DownloadedVideo, SessionValidation
 
 __all__ = [
-    "DownloadedVideo",
-    "InvalidSessionError",
-    "InvalidUrlError",
-    "JsRuntimeUnavailableError",
-    "PathInput",
-    "SessionValidation",
-    "VideoDownloadError",
-    "YtShortsDownloaderError",
-    "download",
-    "download_short",
-    "download_to_path",
-    "validate_session_file",
+    'DownloadedVideo',
+    'InvalidSessionError',
+    'InvalidUrlError',
+    'JsRuntimeUnavailableError',
+    'PathInput',
+    'SessionValidation',
+    'VideoDownloadError',
+    'YtShortsDownloaderError',
+    'download',
+    'download_short',
+    'download_to_path',
+    'validate_session_file',
 ]

src/yt_shorts_downloader/__main__.py

@@ -2,5 +2,5 @@ from __future__ import annotations
 
 from .cli import main
 
-if __name__ == "__main__":
+if __name__ == '__main__':
     raise SystemExit(main())

src/yt_shorts_downloader/api.py

@@ -13,11 +13,11 @@ from .services.session import validate_session_file
 PathInput = str | PathLike[str]
 
 __all__ = [
-    "PathInput",
-    "download",
-    "download_short",
-    "download_to_path",
-    "validate_session_file",
+    'PathInput',
+    'download',
+    'download_short',
+    'download_to_path',
+    'validate_session_file',
 ]
 
 
@@ -25,10 +25,11 @@ def download(
     url: str,
     session_path: PathInput,
 ) -> DownloadedVideo:
+    """Download a YouTube Short and return its MP4 bytes in memory."""
     validate_youtube_url(url)
     normalized_session_path = _normalize_session_path(session_path)
 
-    with TemporaryDirectory(prefix="yt-shorts-downloader-") as temporary_directory:
+    with TemporaryDirectory(prefix='yt-shorts-downloader-') as temporary_directory:
         downloaded_file = download_video(
             url=url,
             output_dir=Path(temporary_directory),
@@ -41,6 +42,7 @@ def download_short(
     url: str,
     session_path: PathInput,
 ) -> DownloadedVideo:
+    """Alias for download kept for API readability."""
     return download(url=url, session_path=session_path)
 
 
@@ -50,6 +52,7 @@ def download_to_path(
     *,
     output_dir: PathInput | None = None,
 ) -> Path:
+    """Download a YouTube Short and persist the resulting MP4 to disk."""
     validate_youtube_url(url)
     normalized_session_path = _normalize_session_path(session_path)
     normalized_output_dir = _normalize_output_dir(output_dir)
@@ -69,10 +72,7 @@ def _normalize_session_path(session_path: PathInput) -> Path:
 
 
 def _normalize_output_dir(output_dir: PathInput | None) -> Path:
-    if output_dir is None:
-        normalized_output_dir = Path.cwd()
-    else:
-        normalized_output_dir = Path(output_dir).expanduser().resolve()
+    normalized_output_dir = Path.cwd() if output_dir is None else Path(output_dir).expanduser().resolve()
 
     normalized_output_dir.mkdir(parents=True, exist_ok=True)
     return normalized_output_dir
@@ -81,9 +81,9 @@ def _normalize_output_dir(output_dir: PathInput | None) -> Path:
 def _read_downloaded_video(downloaded_file: Path) -> DownloadedVideo:
     normalized_downloaded_file = downloaded_file.expanduser().resolve()
     if not normalized_downloaded_file.exists():
-        raise VideoDownloadError("Скачивание завершилось без итогового файла на диске")
-    if normalized_downloaded_file.suffix.lower() != ".mp4":
-        raise VideoDownloadError("Публичный API поддерживает только итоговый MP4")
+        raise VideoDownloadError('Скачивание завершилось без итогового файла на диске')
+    if normalized_downloaded_file.suffix.lower() != '.mp4':
+        raise VideoDownloadError('Публичный API поддерживает только итоговый MP4')
 
     return DownloadedVideo(
         filename=normalized_downloaded_file.name,

src/yt_shorts_downloader/cli.py

@@ -9,25 +9,27 @@ from .exceptions import YtShortsDownloaderError
 
 
 def build_parser() -> argparse.ArgumentParser:
+    """Build the CLI argument parser."""
     parser = argparse.ArgumentParser(
-        description=("Скачать YouTube Shorts через session file в Netscape cookie format."),
+        description=('Скачать YouTube Shorts через session file в Netscape cookie format.'),
     )
-    parser.add_argument("url", help="Ссылка на YouTube Shorts")
+    parser.add_argument('url', help='Ссылка на YouTube Shorts')
     parser.add_argument(
-        "session_path",
+        'session_path',
         type=Path,
-        help="Путь до session file в Netscape cookie format",
+        help='Путь до session file в Netscape cookie format',
     )
     parser.add_argument(
-        "--output-dir",
+        '--output-dir',
         type=Path,
-        default=Path("."),
-        help="Папка, куда сохранить скачанный файл",
+        default=Path('.'),
+        help='Папка, куда сохранить скачанный файл',
     )
     return parser
 
 
 def main(argv: Sequence[str] | None = None) -> int:
+    """Run the CLI entrypoint and return the exit code."""
     parser = build_parser()
     args = parser.parse_args(argv)
 
@@ -38,7 +40,7 @@ def main(argv: Sequence[str] | None = None) -> int:
             output_dir=args.output_dir,
         )
     except YtShortsDownloaderError as exc:
-        parser.exit(status=1, message=f"[error] {exc}\n")
+        parser.exit(status=1, message=f'[error] {exc}\n')
 
     print(downloaded_file)
     return 0

src/yt_shorts_downloader/core/__init__.py

@@ -5,8 +5,8 @@ from .runtime import JsRuntimeOptions, find_supported_js_runtimes
 from .urls import validate_youtube_url
 
 __all__ = [
-    "JsRuntimeOptions",
-    "download_video",
-    "find_supported_js_runtimes",
-    "validate_youtube_url",
+    'JsRuntimeOptions',
+    'download_video',
+    'find_supported_js_runtimes',
+    'validate_youtube_url',
 ]

src/yt_shorts_downloader/core/downloader.py

@@ -14,70 +14,67 @@ from .runtime import JsRuntimeOptions, find_supported_js_runtimes
 type Metadata = dict[str, object]
 type YtDlpOptions = dict[str, object]
 
-_DEFAULT_OUTTMPL: Final[str] = "%(title).200B [%(id)s].%(ext)s"
+_DEFAULT_OUTTMPL: Final[str] = '%(title).200B [%(id)s].%(ext)s'
 
 
 def download_video(url: str, output_dir: Path, session_path: Path) -> Path:
+    """Download a video with yt-dlp and return the final MP4 path."""
     options = _build_yt_dlp_options(output_dir=output_dir, session_path=session_path)
 
     try:
         with YoutubeDL(options) as youtube_downloader:
             extracted_info = youtube_downloader.extract_info(url, download=True)
     except UnsupportedError as exc:
-        raise InvalidUrlError(f"yt-dlp не поддерживает эту ссылку: {exc}") from exc
+        raise InvalidUrlError(f'yt-dlp не поддерживает эту ссылку: {exc}') from exc
     except YtDlpDownloadError as exc:
-        raise VideoDownloadError(f"Не удалось скачать видео: {exc}") from exc
+        raise VideoDownloadError(f'Не удалось скачать видео: {exc}') from exc
 
     if not isinstance(extracted_info, dict):
-        raise VideoDownloadError("yt-dlp вернул неожиданный формат метаданных")
+        raise VideoDownloadError('yt-dlp вернул неожиданный формат метаданных')
 
     downloaded_file = _locate_downloaded_file(
         info=cast(Metadata, extracted_info),
         output_dir=output_dir,
     )
     if downloaded_file is None:
-        raise VideoDownloadError(
-            "Скачивание завершено, но итоговый путь к файлу определить не удалось"
-        )
-    if downloaded_file.suffix.lower() != ".mp4":
-        raise VideoDownloadError("Итоговый файл не является MP4")
+        raise VideoDownloadError('Скачивание завершено, но итоговый путь к файлу определить не удалось')
+    if downloaded_file.suffix.lower() != '.mp4':
+        raise VideoDownloadError('Итоговый файл не является MP4')
 
     return downloaded_file
 
 
 def _build_yt_dlp_options(output_dir: Path, session_path: Path) -> YtDlpOptions:
     js_runtimes = _get_supported_js_runtimes()
-    ffmpeg_available = which("ffmpeg") is not None
-    format_selector = "bv*[ext=mp4]+ba[ext=m4a]/b[ext=mp4]" if ffmpeg_available else "b[ext=mp4]"
+    ffmpeg_available = which('ffmpeg') is not None
+    format_selector = 'bv*[ext=mp4]+ba[ext=m4a]/b[ext=mp4]' if ffmpeg_available else 'b[ext=mp4]'
 
     return {
-        "cookiefile": str(session_path),
-        "format": format_selector,
-        "js_runtimes": js_runtimes,
-        "merge_output_format": "mp4",
-        "no_warnings": True,
-        "noplaylist": True,
-        "noprogress": True,
-        "outtmpl": str(output_dir / _DEFAULT_OUTTMPL),
-        "overwrites": False,
-        "quiet": True,
+        'cookiefile': str(session_path),
+        'format': format_selector,
+        'js_runtimes': js_runtimes,
+        'merge_output_format': 'mp4',
+        'no_warnings': True,
+        'noplaylist': True,
+        'noprogress': True,
+        'outtmpl': str(output_dir / _DEFAULT_OUTTMPL),
+        'overwrites': False,
+        'quiet': True,
     }
 
 
 def _get_supported_js_runtimes() -> JsRuntimeOptions:
     js_runtimes = find_supported_js_runtimes()
     if js_runtimes is None:
-        raise JsRuntimeUnavailableError(
-            "Не найден поддерживаемый JavaScript runtime. Установите deno или Node.js 22+."
-        )
+        raise JsRuntimeUnavailableError('Не найден поддерживаемый JavaScript runtime. Установите deno или Node.js 22+.')
     return js_runtimes
 
 
 def _unwrap_info(info: Metadata) -> Metadata:
-    if info.get("_type") != "playlist":
+    if info.get('_type') != 'playlist':
         return info
 
-    entries = info.get("entries")
+    entries = info.get('entries')
     if not isinstance(entries, list):
         return info
 
@@ -90,30 +87,30 @@ def _unwrap_info(info: Metadata) -> Metadata:
 def _locate_downloaded_file(info: Metadata, output_dir: Path) -> Path | None:
     normalized_info = _unwrap_info(info)
 
-    requested_downloads = normalized_info.get("requested_downloads")
+    requested_downloads = normalized_info.get('requested_downloads')
     if isinstance(requested_downloads, list):
         for item in requested_downloads:
             if not isinstance(item, dict):
                 continue
-            filepath = item.get("filepath")
+            filepath = item.get('filepath')
             if isinstance(filepath, str):
                 candidate = Path(filepath)
                 if candidate.exists():
                     return candidate
 
-    for key in ("filepath", "_filename"):
+    for key in ('filepath', '_filename'):
         filepath = normalized_info.get(key)
         if isinstance(filepath, str):
             candidate = Path(filepath)
             if candidate.exists():
                 return candidate
 
-    video_id = normalized_info.get("id")
+    video_id = normalized_info.get('id')
     if not isinstance(video_id, str):
         return None
 
     matches = sorted(
-        (path for path in output_dir.iterdir() if path.is_file() and f"[{video_id}]" in path.name),
+        (path for path in output_dir.iterdir() if path.is_file() and f'[{video_id}]' in path.name),
         key=lambda path: path.stat().st_mtime,
         reverse=True,
     )

src/yt_shorts_downloader/core/runtime.py

@@ -7,41 +7,41 @@ from shutil import which
 type JsRuntimeOptions = dict[str, dict[str, str]]
 
 _MIN_NODE_VERSION = (22, 0, 0)
+_SEMVER_PART_COUNT = 3
 
 
 def find_supported_js_runtimes() -> JsRuntimeOptions | None:
-    deno_path = which("deno")
+    """Return the best supported JavaScript runtime for yt-dlp."""
+    deno_path = which('deno')
     if deno_path is not None:
-        return {"deno": {"path": deno_path}}
+        return {'deno': {'path': deno_path}}
 
     node_candidates: dict[str, tuple[int, int, int]] = {}
-    node_on_path = which("node")
+    node_on_path = which('node')
     if node_on_path is not None:
         version = _probe_executable_version(node_on_path)
         if version is not None:
             node_candidates[str(Path(node_on_path).resolve())] = version
 
-    nvm_versions_dir = Path.home() / ".nvm" / "versions" / "node"
+    nvm_versions_dir = Path.home() / '.nvm' / 'versions' / 'node'
     if nvm_versions_dir.exists():
-        for candidate in nvm_versions_dir.glob("v*/bin/node"):
+        for candidate in nvm_versions_dir.glob('v*/bin/node'):
             version = _probe_executable_version(str(candidate))
             if version is not None:
                 node_candidates[str(candidate.resolve())] = version
 
-    supported_nodes = {
-        path: version for path, version in node_candidates.items() if version >= _MIN_NODE_VERSION
-    }
+    supported_nodes = {path: version for path, version in node_candidates.items() if version >= _MIN_NODE_VERSION}
     if not supported_nodes:
         return None
 
     best_node_path = max(supported_nodes, key=lambda path: supported_nodes[path])
-    return {"node": {"path": best_node_path}}
+    return {'node': {'path': best_node_path}}
 
 
 def _probe_executable_version(executable: str) -> tuple[int, int, int] | None:
     try:
         result = subprocess.run(
-            [executable, "--version"],
+            [executable, '--version'],
             capture_output=True,
             check=False,
             text=True,
@@ -58,12 +58,12 @@ def _probe_executable_version(executable: str) -> tuple[int, int, int] | None:
 
 
 def _parse_semver(value: str) -> tuple[int, int, int] | None:
-    cleaned = value.strip().lstrip("vV")
-    parts = cleaned.split(".")
+    cleaned = value.strip().lstrip('vV')
+    parts = cleaned.split('.')
     numbers: list[int] = []
 
-    for part in parts[:3]:
-        digits = ""
+    for part in parts[:_SEMVER_PART_COUNT]:
+        digits = ''
         for character in part:
             if not character.isdigit():
                 break
@@ -72,7 +72,7 @@ def _parse_semver(value: str) -> tuple[int, int, int] | None:
             return None
         numbers.append(int(digits))
 
-    while len(numbers) < 3:
+    while len(numbers) < _SEMVER_PART_COUNT:
         numbers.append(0)
 
     return (numbers[0], numbers[1], numbers[2])

src/yt_shorts_downloader/core/urls.py

@@ -4,17 +4,18 @@ from urllib.parse import urlparse
 
 from ..exceptions import InvalidUrlError
 
-_YOUTUBE_HOST_SUFFIXES = ("youtube.com", "youtu.be")
+_YOUTUBE_HOST_SUFFIXES = ('youtube.com', 'youtu.be')
 
 
 def validate_youtube_url(url: str) -> None:
+    """Validate that the input URL points to a supported YouTube host."""
     parsed = urlparse(url)
-    if parsed.scheme not in {"http", "https"}:
-        raise InvalidUrlError("URL должна начинаться с http:// или https://")
+    if parsed.scheme not in {'http', 'https'}:
+        raise InvalidUrlError('URL должна начинаться с http:// или https://')
 
     host = parsed.netloc.lower()
     if not host:
-        raise InvalidUrlError("Не удалось определить домен URL")
+        raise InvalidUrlError('Не удалось определить домен URL')
 
-    if not any(host == suffix or host.endswith(f".{suffix}") for suffix in _YOUTUBE_HOST_SUFFIXES):
-        raise InvalidUrlError("Поддерживаются только ссылки YouTube")
+    if not any(host == suffix or host.endswith(f'.{suffix}') for suffix in _YOUTUBE_HOST_SUFFIXES):
+        raise InvalidUrlError('Поддерживаются только ссылки YouTube')

src/yt_shorts_downloader/downloader.py

@@ -2,4 +2,4 @@ from __future__ import annotations
 
 from .core.downloader import download_video
 
-__all__ = ["download_video"]
+__all__ = ['download_video']

src/yt_shorts_downloader/exceptions.py

@@ -2,20 +2,30 @@ from __future__ import annotations
 
 
 class YtShortsDownloaderError(Exception):
+    """Base exception for package-specific failures."""
+
     pass
 
 
 class InvalidUrlError(YtShortsDownloaderError):
+    """Raised when the provided URL is not a supported YouTube URL."""
+
     pass
 
 
 class InvalidSessionError(YtShortsDownloaderError):
+    """Raised when the provided session file cannot be used."""
+
     pass
 
 
 class JsRuntimeUnavailableError(YtShortsDownloaderError):
+    """Raised when no supported JavaScript runtime is available."""
+
     pass
 
 
 class VideoDownloadError(YtShortsDownloaderError):
+    """Raised when yt-dlp cannot produce a valid MP4 result."""
+
     pass

src/yt_shorts_downloader/models/__init__.py

@@ -3,4 +3,4 @@ from __future__ import annotations
 from .download import DownloadedVideo
 from .session import SessionCookie, SessionValidation
 
-__all__ = ["DownloadedVideo", "SessionCookie", "SessionValidation"]
+__all__ = ['DownloadedVideo', 'SessionCookie', 'SessionValidation']

src/yt_shorts_downloader/models/download.py

@@ -5,6 +5,8 @@ from dataclasses import dataclass
 
 @dataclass(frozen=True, slots=True)
 class DownloadedVideo:
+    """In-memory representation of a downloaded MP4 file."""
+
     filename: str
     content: bytes
-    media_type: str = "video/mp4"
+    media_type: str = 'video/mp4'

src/yt_shorts_downloader/models/session.py

@@ -5,6 +5,8 @@ from dataclasses import dataclass
 
 @dataclass(frozen=True, slots=True)
 class SessionCookie:
+    """Normalized cookie parsed from a Netscape session file."""
+
     domain: str
     include_subdomains: bool
     path: str
@@ -16,6 +18,8 @@ class SessionCookie:
 
 @dataclass(frozen=True, slots=True)
 class SessionValidation:
+    """Validation result for a candidate session cookie file."""
+
     exists: bool
     structurally_valid: bool
     fresh: bool

src/yt_shorts_downloader/runtime.py

@@ -2,4 +2,4 @@ from __future__ import annotations
 
 from .core.runtime import JsRuntimeOptions, _parse_semver, find_supported_js_runtimes
 
-__all__ = ["JsRuntimeOptions", "_parse_semver", "find_supported_js_runtimes"]
+__all__ = ['JsRuntimeOptions', '_parse_semver', 'find_supported_js_runtimes']

src/yt_shorts_downloader/services/__init__.py

@@ -2,4 +2,4 @@ from __future__ import annotations
 
 from .session import validate_session_file
 
-__all__ = ["validate_session_file"]
+__all__ = ['validate_session_file']

src/yt_shorts_downloader/services/session.py

@@ -5,27 +5,30 @@ from pathlib import Path
 
 from ..models import SessionCookie, SessionValidation
 
-_SESSION_DOMAIN_SUFFIXES = ("youtube.com", "google.com")
+_SESSION_DOMAIN_SUFFIXES = ('youtube.com', 'google.com')
 _AUTH_COOKIE_NAMES = {
-    "SID",
-    "HSID",
-    "SSID",
-    "APISID",
-    "SAPISID",
-    "__Secure-1PSID",
-    "__Secure-3PSID",
-    "LOGIN_INFO",
+    'SID',
+    'HSID',
+    'SSID',
+    'APISID',
+    'SAPISID',
+    '__Secure-1PSID',
+    '__Secure-3PSID',
+    'LOGIN_INFO',
 }
 _AUTH_COOKIE_ANCHORS = {
-    "SID",
-    "SAPISID",
-    "__Secure-1PSID",
-    "__Secure-3PSID",
-    "LOGIN_INFO",
+    'SID',
+    'SAPISID',
+    '__Secure-1PSID',
+    '__Secure-3PSID',
+    'LOGIN_INFO',
 }
+_MIN_FRESH_AUTH_COOKIES = 3
+_NETSCAPE_COOKIE_COLUMNS = 7
 
 
 def validate_session_file(path: Path) -> SessionValidation:
+    """Validate that a Netscape cookie file is usable for YouTube downloads."""
     normalized_path = path.expanduser().resolve()
     if not normalized_path.exists():
         return SessionValidation(
@@ -33,7 +36,7 @@ def validate_session_file(path: Path) -> SessionValidation:
             structurally_valid=False,
             fresh=False,
             is_usable=False,
-            message=f"Файл сессии не найден: {normalized_path}",
+            message=f'Файл сессии не найден: {normalized_path}',
         )
 
     try:
@@ -44,7 +47,7 @@ def validate_session_file(path: Path) -> SessionValidation:
             structurally_valid=False,
             fresh=False,
             is_usable=False,
-            message=f"Файл сессии не прошёл проверку формата: {exc}",
+            message=f'Файл сессии не прошёл проверку формата: {exc}',
         )
 
     if not cookies:
@@ -53,19 +56,17 @@ def validate_session_file(path: Path) -> SessionValidation:
             structurally_valid=False,
             fresh=False,
             is_usable=False,
-            message="Файл сессии пустой",
+            message='Файл сессии пустой',
         )
 
-    relevant_cookies = [
-        cookie for cookie in cookies if _matches_domain(cookie.domain, _SESSION_DOMAIN_SUFFIXES)
-    ]
+    relevant_cookies = [cookie for cookie in cookies if _matches_domain(cookie.domain, _SESSION_DOMAIN_SUFFIXES)]
     if not relevant_cookies:
         return SessionValidation(
             exists=True,
             structurally_valid=False,
             fresh=False,
             is_usable=False,
-            message="В файле сессии нет записей для YouTube или Google",
+            message='В файле сессии нет записей для YouTube или Google',
         )
 
     now = int(time.time())
@@ -83,26 +84,20 @@ def validate_session_file(path: Path) -> SessionValidation:
             soonest_expiry = cookie.expires
 
     anchor_count = len(fresh_auth_names & _AUTH_COOKIE_ANCHORS)
-    fresh = len(fresh_auth_names) >= 3 and anchor_count >= 1
+    fresh = len(fresh_auth_names) >= _MIN_FRESH_AUTH_COOKIES and anchor_count >= 1
     if not fresh:
         return SessionValidation(
             exists=True,
             structurally_valid=True,
             fresh=False,
             is_usable=False,
-            message=(
-                "Файл сессии в корректном формате, но в нём нет достаточного набора "
-                "актуальных YouTube auth-cookie"
-            ),
+            message=('Файл сессии в корректном формате, но в нём нет достаточного набора актуальных YouTube auth-cookie'),
         )
 
-    message = (
-        "Файл сессии валиден и выглядит актуальным для YouTube: "
-        f"найдено {len(fresh_auth_names)} свежих auth-cookie"
-    )
+    message = f'Файл сессии валиден и выглядит актуальным для YouTube: найдено {len(fresh_auth_names)} свежих auth-cookie'
     if soonest_expiry is not None:
         hours_left = max((soonest_expiry - now) // 3600, 0)
-        message += f", ближайшее истечение примерно через {hours_left} ч"
+        message += f', ближайшее истечение примерно через {hours_left} ч'
 
     return SessionValidation(
         exists=True,
@@ -116,26 +111,22 @@ def validate_session_file(path: Path) -> SessionValidation:
 def _parse_session_file(path: Path) -> list[SessionCookie]:
     cookies: list[SessionCookie] = []
 
-    with path.open("r", encoding="utf-8") as handle:
+    with path.open('r', encoding='utf-8') as handle:
         for line_number, raw_line in enumerate(handle, start=1):
             stripped = raw_line.strip()
             if not stripped:
                 continue
 
-            is_httponly_cookie = stripped.startswith("#HttpOnly_")
-            if stripped.startswith("#") and not is_httponly_cookie:
+            is_httponly_cookie = stripped.startswith('#HttpOnly_')
+            if stripped.startswith('#') and not is_httponly_cookie:
                 continue
 
             if is_httponly_cookie:
-                stripped = stripped.removeprefix("#HttpOnly_")
+                stripped = stripped.removeprefix('#HttpOnly_')
 
-            parts = stripped.split("\t")
-            if len(parts) != 7:
-                raise ValueError(
-                    "Строка "
-                    f"{line_number}: ожидалось 7 колонок Netscape cookie file, "
-                    f"получено {len(parts)}"
-                )
+            parts = stripped.split('\t')
+            if len(parts) != _NETSCAPE_COOKIE_COLUMNS:
+                raise ValueError(f'Строка {line_number}: ожидалось {_NETSCAPE_COOKIE_COLUMNS} колонок Netscape cookie file, получено {len(parts)}')
 
             (
                 domain,
@@ -150,16 +141,14 @@ def _parse_session_file(path: Path) -> list[SessionCookie]:
             try:
                 expires_at = int(expires)
             except ValueError as exc:
-                raise ValueError(
-                    f"Строка {line_number}: expires должен быть UNIX timestamp"
-                ) from exc
+                raise ValueError(f'Строка {line_number}: expires должен быть UNIX timestamp') from exc
 
             cookies.append(
                 SessionCookie(
                     domain=domain,
-                    include_subdomains=include_subdomains.upper() == "TRUE",
+                    include_subdomains=include_subdomains.upper() == 'TRUE',
                     path=cookie_path,
-                    secure=secure.upper() == "TRUE",
+                    secure=secure.upper() == 'TRUE',
                     expires=expires_at,
                     name=name,
                     value=value,
@@ -171,11 +160,8 @@ def _parse_session_file(path: Path) -> list[SessionCookie]:
 
 def _matches_domain(domain: str, suffixes: tuple[str, ...]) -> bool:
     normalized_domain = _normalize_domain(domain)
-    return any(
-        normalized_domain == suffix or normalized_domain.endswith(f".{suffix}")
-        for suffix in suffixes
-    )
+    return any(normalized_domain == suffix or normalized_domain.endswith(f'.{suffix}') for suffix in suffixes)
 
 
 def _normalize_domain(domain: str) -> str:
-    return domain.removeprefix("#HttpOnly_").lstrip(".").lower()
+    return domain.removeprefix('#HttpOnly_').lstrip('.').lower()

src/yt_shorts_downloader/session.py

@@ -2,4 +2,4 @@ from __future__ import annotations
 
 from .services.session import validate_session_file
 
-__all__ = ["validate_session_file"]
+__all__ = ['validate_session_file']

tests/test_api.py

@@ -14,50 +14,48 @@ def _build_valid_session_validation(path: Path) -> SessionValidation:
 
 
 def test_download_returns_binary_mp4(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
-    expected_content = b"mp4-binary-content"
+    expected_content = b'mp4-binary-content'
 
     def fake_validate_session_file(path: Path) -> SessionValidation:
         return _build_valid_session_validation(path)
 
     def fake_download_video(*, url: str, output_dir: Path, session_path: Path) -> Path:
         del url, session_path
-        downloaded_file = output_dir / "video.mp4"
+        downloaded_file = output_dir / 'video.mp4'
         downloaded_file.write_bytes(expected_content)
         return downloaded_file
 
-    monkeypatch.setattr(api, "validate_session_file", fake_validate_session_file)
-    monkeypatch.setattr(api, "download_video", fake_download_video)
+    monkeypatch.setattr(api, 'validate_session_file', fake_validate_session_file)
+    monkeypatch.setattr(api, 'download_video', fake_download_video)
 
     downloaded_video = api.download(
-        "https://youtube.com/shorts/example",
-        session_path="cookies.txt",
+        'https://youtube.com/shorts/example',
+        session_path='cookies.txt',
     )
 
     assert downloaded_video == DownloadedVideo(
-        filename="video.mp4",
+        filename='video.mp4',
         content=expected_content,
     )
 
 
-def test_download_to_path_returns_path_from_downloader(
-    monkeypatch: pytest.MonkeyPatch, tmp_path: Path
-) -> None:
-    expected_path = tmp_path / "video.mp4"
+def test_download_to_path_returns_path_from_downloader(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
+    expected_path = tmp_path / 'video.mp4'
 
     def fake_validate_session_file(path: Path) -> SessionValidation:
         return _build_valid_session_validation(path)
 
     def fake_download_video(*, url: str, output_dir: Path, session_path: Path) -> Path:
         del url, session_path
-        expected_path.write_bytes(b"mp4")
+        expected_path.write_bytes(b'mp4')
         return output_dir / expected_path.name
 
-    monkeypatch.setattr(api, "validate_session_file", fake_validate_session_file)
-    monkeypatch.setattr(api, "download_video", fake_download_video)
+    monkeypatch.setattr(api, 'validate_session_file', fake_validate_session_file)
+    monkeypatch.setattr(api, 'download_video', fake_download_video)
 
     downloaded_path = api.download_to_path(
-        "https://youtube.com/shorts/example",
-        session_path="cookies.txt",
+        'https://youtube.com/shorts/example',
+        session_path='cookies.txt',
         output_dir=tmp_path,
     )
 
@@ -66,15 +64,15 @@ def test_download_to_path_returns_path_from_downloader(
 
 def test_download_rejects_invalid_url() -> None:
     with pytest.raises(InvalidUrlError):
-        api.download("https://example.com/watch?v=1", session_path="cookies.txt")
+        api.download('https://example.com/watch?v=1', session_path='cookies.txt')
 
 
 def test_download_rejects_invalid_session(monkeypatch: pytest.MonkeyPatch) -> None:
     def fake_validate_session_file(path: Path) -> SessionValidation:
         del path
-        return SessionValidation(False, False, False, False, "bad session")
+        return SessionValidation(False, False, False, False, 'bad session')
 
-    monkeypatch.setattr(api, "validate_session_file", fake_validate_session_file)
+    monkeypatch.setattr(api, 'validate_session_file', fake_validate_session_file)
 
-    with pytest.raises(InvalidSessionError, match="bad session"):
-        api.download("https://youtube.com/shorts/example", session_path="cookies.txt")
+    with pytest.raises(InvalidSessionError, match='bad session'):
+        api.download('https://youtube.com/shorts/example', session_path='cookies.txt')

tests/test_cli.py

@@ -13,19 +13,19 @@ def test_cli_prints_downloaded_path(
     capsys: pytest.CaptureFixture[str],
     tmp_path: Path,
 ) -> None:
-    expected_path = tmp_path / "video.mp4"
+    expected_path = tmp_path / 'video.mp4'
 
     def fake_download_to_path(**kwargs: object) -> Path:
         del kwargs
         return expected_path
 
-    monkeypatch.setattr(cli, "download_to_path", fake_download_to_path)
+    monkeypatch.setattr(cli, 'download_to_path', fake_download_to_path)
 
     exit_code = cli.main(
         [
-            "https://youtube.com/shorts/example",
-            "cookies.txt",
-            "--output-dir",
+            'https://youtube.com/shorts/example',
+            'cookies.txt',
+            '--output-dir',
             str(tmp_path),
         ]
     )
@@ -39,11 +39,11 @@ def test_cli_prints_downloaded_path(
 def test_cli_exits_with_error(monkeypatch: pytest.MonkeyPatch) -> None:
     def raise_error(**kwargs: object) -> Path:
         del kwargs
-        raise InvalidSessionError("session error")
+        raise InvalidSessionError('session error')
 
-    monkeypatch.setattr(cli, "download_to_path", raise_error)
+    monkeypatch.setattr(cli, 'download_to_path', raise_error)
 
     with pytest.raises(SystemExit) as exc_info:
-        cli.main(["https://youtube.com/shorts/example", "cookies.txt"])
+        cli.main(['https://youtube.com/shorts/example', 'cookies.txt'])
 
     assert exc_info.value.code == 1

tests/test_runtime.py

@@ -12,39 +12,42 @@ def test_find_supported_js_runtimes_prefers_deno(
 ) -> None:
     monkeypatch.setattr(
         runtime,
-        "which",
-        lambda executable: "/usr/bin/deno" if executable == "deno" else None,
+        'which',
+        lambda executable: '/usr/bin/deno' if executable == 'deno' else None,
     )
 
     runtimes = runtime.find_supported_js_runtimes()
 
-    assert runtimes == {"deno": {"path": "/usr/bin/deno"}}
+    assert runtimes == {'deno': {'path': '/usr/bin/deno'}}
 
 
 def test_find_supported_js_runtimes_uses_best_supported_node(
     monkeypatch: pytest.MonkeyPatch,
     tmp_path: Path,
 ) -> None:
-    first_node = tmp_path / ".nvm" / "versions" / "node" / "v22.1.0" / "bin" / "node"
-    second_node = tmp_path / ".nvm" / "versions" / "node" / "v22.9.0" / "bin" / "node"
+    first_node = tmp_path / '.nvm' / 'versions' / 'node' / 'v22.1.0' / 'bin' / 'node'
+    second_node = tmp_path / '.nvm' / 'versions' / 'node' / 'v22.9.0' / 'bin' / 'node'
     second_node.parent.mkdir(parents=True)
     first_node.parent.mkdir(parents=True)
-    first_node.write_text("", encoding="utf-8")
-    second_node.write_text("", encoding="utf-8")
+    first_node.write_text('', encoding='utf-8')
+    second_node.write_text('', encoding='utf-8')
 
-    monkeypatch.setattr(runtime, "which", lambda executable: None)
-    monkeypatch.setattr(Path, "home", lambda: tmp_path)
+    def fake_which(_executable: str) -> None:
+        return None
+
+    monkeypatch.setattr(runtime, 'which', fake_which)
+    monkeypatch.setattr(Path, 'home', lambda: tmp_path)
     monkeypatch.setattr(
         runtime,
-        "_probe_executable_version",
-        lambda executable: (22, 9, 0) if executable.endswith("v22.9.0/bin/node") else (22, 1, 0),
+        '_probe_executable_version',
+        lambda executable: (22, 9, 0) if executable.endswith('v22.9.0/bin/node') else (22, 1, 0),
     )
 
     runtimes = runtime.find_supported_js_runtimes()
 
-    assert runtimes == {"node": {"path": str(second_node.resolve())}}
+    assert runtimes == {'node': {'path': str(second_node.resolve())}}
 
 
 def test_parse_semver_handles_prefixed_versions() -> None:
-    assert runtime._parse_semver("v22.12.1") == (22, 12, 1)
-    assert runtime._parse_semver("node") is None
+    assert runtime._parse_semver('v22.12.1') == (22, 12, 1)
+    assert runtime._parse_semver('node') is None

tests/test_session.py

@@ -6,17 +6,17 @@ from yt_shorts_downloader.session import validate_session_file
 
 
 def test_validate_session_file_accepts_valid_youtube_session(tmp_path: Path) -> None:
-    session_file = tmp_path / "cookies.txt"
+    session_file = tmp_path / 'cookies.txt'
     session_file.write_text(
-        "\n".join(
+        '\n'.join(
             [
-                "# Netscape HTTP Cookie File",
-                ".youtube.com\tTRUE\t/\tFALSE\t9999999999\tSID\tvalue1",
-                ".youtube.com\tTRUE\t/\tTRUE\t9999999999\tSAPISID\tvalue2",
-                ".youtube.com\tTRUE\t/\tTRUE\t9999999999\tLOGIN_INFO\tvalue3",
+                '# Netscape HTTP Cookie File',
+                '.youtube.com\tTRUE\t/\tFALSE\t9999999999\tSID\tvalue1',
+                '.youtube.com\tTRUE\t/\tTRUE\t9999999999\tSAPISID\tvalue2',
+                '.youtube.com\tTRUE\t/\tTRUE\t9999999999\tLOGIN_INFO\tvalue3',
             ]
         ),
-        encoding="utf-8",
+        encoding='utf-8',
     )
 
     validation = validate_session_file(session_file)
@@ -28,8 +28,8 @@ def test_validate_session_file_accepts_valid_youtube_session(tmp_path: Path) ->
 
 
 def test_validate_session_file_rejects_invalid_format(tmp_path: Path) -> None:
-    session_file = tmp_path / "cookies.txt"
-    session_file.write_text("broken\trow", encoding="utf-8")
+    session_file = tmp_path / 'cookies.txt'
+    session_file.write_text('broken\trow', encoding='utf-8')
 
     validation = validate_session_file(session_file)