Archived
snowy-yang
9910e4dbec
为什么：_fetch_via_http 是全仓内置下载通道的落盘实现，也是本文件此前最大的
圈复杂度所在。94 行的单体里叠着三段互不相关的职责——Range 起点校验、流式写盘
与体积上限、HTTP 错误分类——还共享一个 try/except/finally。上一轮拆
download_music_file 时它是唯一没动的重函数。
改法：拆成 7 个具名成员，主函数只留四步编排（构造 Range 头 → 发请求 →
定追加/重写并校验分片起点 → 流式落盘）。
_range_headers 续传时请求「起点之后的全部字节」
_resolve_write_mode 续传且服务器确实给 206 才追加，否则从头重写
_verify_content_range 校验 206 分片起点；无法确认就清残片从头下
_stream_body 逐块写盘 + 取消检查 + 体积硬上限（500MB）
_safe_progress 上报进度，回调异常吞掉（原两处 try/except 收敛）
_http_status 从 HTTPError 取状态码
_is_deterministic_client_error 4xx 判定（408 例外，唯一保留可重试的 4xx）
复杂度（同口径 AST 实测，HEAD 与工作区用同一脚本）：
_fetch_via_http 94 行 / 圈 21 / 嵌套 7 → 46 行 / 圈 5 / 嵌套 3
文件内最大圈复杂度 21（当时就是它） → 16（余下最大是 download_music_file）
文件行数 710 → 753（+43，全是新签名与 docstring）· 函数数 19 → 26
口径说明：上一轮口头报的「圈 35」用的是另一脚本（另计入布尔运算与比较），
本轮 HEAD 同口径实测为 21。以本轮为准——HEAD 与重构后由同一脚本测出，可比。
等价性证据（两道，互相独立）：
1. 反向注入验证：把 HEAD 版 downloader 注入成 music_downloader.downloader，用同一套
tests/test_downloader.py 跑 → 30 例**全过**。证明这批测试忠实编码了旧行为，
因而对新实现构成等价性验证（含本次新增的 5xx 用例，它在旧实现上同样通过）。
2. AST 字面量多重集比对 + 逐条位置定位：数值/布尔 26 种、字符串 80 种，
差异全部归因，且**没有一条用户可见文案或阈值被改动**：
206 2→1：旧的两段独立 if（`!= 206` 归零 mode、`== 206` 校验起点）合并进
_resolve_write_mode 的一个判断
0 26→24：两处 progress 的 `or 0` 收敛成 expected_size（-1）；
两处 206 判断各含一个 `> 0` 合并成一个 `<= 0`（-1）
'wb' 2→1：初始赋值与条件改写两处合并成一个 return
500MB 阈值、各条错误文案原样保留。
重写条件表达式必须补分支穷举（字面量审计不管这一层），已逐路核对：
resume_from <= 0 → 'wb'（旧：不进任何 if，保持初始 'wb'）
resume_from > 0 且 status != 206 → 'wb'（旧：第一个 if 命中）
resume_from > 0 且 status == 206 → 校验起点 + 'ab'（旧：第二个 if 命中）
三路与旧实现一致。
刻意保留的语义（是决定，不是疏漏）：
- 超限清理仍**延后到 with 退出后**——Windows 无法删除仍被打开的文件，原实现在
打开中 unlink 被静默吞掉，残片会留在磁盘上。
- 进度回调异常一律吞掉，绝不影响下载主流程。
- 4xx 里 408 是唯一例外（保留可重试）；416 与「206 头被剥离解析不出起点」同口径
清残片从头下（盲追加拼出的是坏文件）。
- 非 416/4xx 的错误走**裸 raise**（不用 `raise e`），保持原 traceback 不被改动。
测试：新增 1 例 test_5xx_is_retried_and_keeps_part —— 5xx 是服务端瞬时故障而非
确定性失败，须可重试且保留 .part 供续传。这条路径此前无覆盖，且它正是
_is_deterministic_client_error 与 4xx 的分界所在。
顺带记录一个验证工具自身的坑（第一次跑反向注入时 30 例全红，看似「测试不忠实」，
实为注入没生效、测试静默走了真实网络，报错为 Cannot connect to host cdn.test）：
只覆盖 sys.modules['music_downloader.downloader'] 不够——pytest 的 monkeypatch
解析目标字符串走 _pytest.monkeypatch.resolve()，是「逐级 getattr 父包」而非纯
sys.modules 查找，包的 downloader 属性仍指向真模块。必须同时 setattr 父包属性。
教训：等价性验证的**工具本身**也要能证伪，否则结论会 180 度反转。
验证：ruff 全过 · pyright 0/0 · pytest 275 passed（274→275）· 行尾 i/lf w/lf
与仓库一致 · 生产 data/ 未被触碰（全部用例走 tmp_path 沙箱）。
602 lines
19 KiB
Python
602 lines
19 KiB
Python
# -*- coding: utf-8 -*-
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"""MusicDownloader.download_music_file 的行为契约测试（沙箱，不触碰生产 data/）。
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为什么：download_music_file 是**唯一**的音频落盘路径——单曲 worker 与音乐批量
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ZIP 都经它，约 205 行 / 圈复杂度 47，此前**零直接测试覆盖**（test_zip_workers 里
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只有一个 stub）。它同时承担缓存校验、断点续传、内容嗅探、体积上限、取消语义、
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重试退避与元数据写入，任何一条被拆坏都不会有测试报警。
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断言只依赖「调用后世界里发生了什么」——返回值、磁盘上的文件、发往网络的请求——
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不引用任何内部函数名，因此本文件可作为后续拆分的等价性验证器。
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替身约定（三处，均为模块级符号，替换点在 downloader 模块命名空间）：
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- 网络：``get_http_session`` / ``get_backend``（后者返回 None = 走内置 HTTP 通道）
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- 内容嗅探：``_sniff_audio_header``（默认放行，按需置 False）
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- 元数据写入：``MusicDownloader._write_metadata``（不真跑 mutagen）
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"""
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import threading
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from pathlib import Path
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from typing import Any
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import pytest
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from core import sync_http
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from music_downloader import DownloadCanceled, DownloadException, MusicInfo
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from music_downloader.downloader import MusicDownloader
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# ============ 替身 ============
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class _FakeResponse:
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"""core.sync_http.SyncResponse 的替身。
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chunks 保留原始 iterable（**不要** list() 归一化）：生成器的副作用
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（如中途置取消位）若在构造时刻就求值，「中途取消」会被悄悄测成
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「开始前取消」——两条不同的路径混成一条，而测试仍是绿的。
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"""
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def __init__(self, chunks, status=200, headers=None):
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self._chunks = chunks
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self.status_code = status
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self.headers = dict(headers or {})
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self.closed = False
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def iter_content(self, chunk_size=0):
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yield from self._chunks
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def raise_for_status(self):
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if self.status_code >= 400:
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raise sync_http.HTTPError(f'HTTP {self.status_code}', self)
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def close(self):
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self.closed = True
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class _FakeSession:
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"""记录每次 GET（含 headers）并按序产出响应。"""
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def __init__(self, responder):
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self._responder = responder
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self.calls: list[tuple[str, dict[str, Any]]] = []
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self.closed = False
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def get(self, url, **kw):
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self.calls.append((url, kw))
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return self._responder(len(self.calls), url, kw)
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def close(self):
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self.closed = True
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def _body(size, status=200, content_range=None):
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"""固定返回 size 字节的响应工厂（每次调用产出新响应对象）。"""
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def _mk(_attempt, _url, _kw):
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headers = {'Content-Range': content_range} if content_range else {}
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return _FakeResponse([b'x' * size], status=status, headers=headers)
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return _mk
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def _info(mid=101, size=20, file_type='mp3'):
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return MusicInfo(
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id=mid, name='测试曲', artists='歌手', album='专辑', pic_url='',
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duration=180, track_number=1, download_url='http://cdn.test/a.mp3',
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file_type=file_type, file_size=size, quality='standard',
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)
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def _paths(dl, info):
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"""按生产同一函数推算落盘路径与 .part 路径（纯函数，可直接复用）。"""
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fp = dl._build_file_path(info)
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return fp, fp.with_name(fp.name + '.part')
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@pytest.fixture()
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def env(tmp_path, monkeypatch):
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"""返回 (downloader, state, install)。
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- state['sniff']：内容嗅探结果，默认 True
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- state['meta']：_write_metadata 的调用记录 [(文件路径, fields), ...]
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- install(responder) -> _FakeSession：安装网络替身，返回该替身以便断言
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"""
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state: dict[str, Any] = {'sniff': True, 'meta': []}
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box: dict[str, _FakeSession] = {}
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def install(responder):
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box['session'] = _FakeSession(responder)
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return box['session']
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def _record_meta(self, file_path, music_info, fields=None):
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state['meta'].append((str(file_path), fields))
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return True
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monkeypatch.setattr('music_downloader.downloader.get_http_session',
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lambda: box['session'])
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monkeypatch.setattr('music_downloader.downloader.get_backend', lambda: None)
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monkeypatch.setattr('music_downloader.downloader._sniff_audio_header',
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lambda _p: state['sniff'])
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monkeypatch.setattr(MusicDownloader, '_write_metadata', _record_meta)
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install(lambda *a: pytest.fail('本用例不应发出网络请求'))
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dl = MusicDownloader(download_dir=str(tmp_path))
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return dl, state, install
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# ============ 正常落盘 ============
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def test_success_promotes_part_to_final(env):
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dl, _state, install = env
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info = _info(size=20)
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fp, part = _paths(dl, info)
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install(_body(20))
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r = dl.download_music_file(101, music_info=info)
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assert r.success and r.error_message == ''
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assert Path(r.file_path) == fp
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assert r.file_size == 20 and fp.read_bytes() == b'x' * 20
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assert not part.exists(), '完成后 .part 应改名转正'
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def test_empty_chunks_skipped(env):
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dl, _state, install = env
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info = _info(size=20)
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fp, _ = _paths(dl, info)
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install(lambda a, u, kw: _FakeResponse([b'', b'x' * 20, b'']))
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seen: list[int] = []
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r = dl.download_music_file(101, music_info=info,
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progress_cb=lambda w, _t: seen.append(w))
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assert r.success and fp.stat().st_size == 20
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assert seen == [0, 20], '空分块不写盘也不触发进度回调'
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def test_progress_reports_resume_start_then_each_chunk(env):
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dl, _state, install = env
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info = _info(size=20)
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install(lambda a, u, kw: _FakeResponse([b'a' * 8, b'b' * 12]))
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seen: list[tuple[int, int]] = []
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r = dl.download_music_file(101, music_info=info,
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progress_cb=lambda w, t: seen.append((w, t)))
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assert r.success
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assert seen == [(0, 20), (8, 20), (20, 20)], '起始回调带续传起点，此后每块一次'
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def test_progress_callback_exception_never_breaks_download(env):
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dl, _state, install = env
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info = _info(size=20)
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install(_body(20))
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def _boom(_w, _t):
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raise RuntimeError('回调炸了')
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r = dl.download_music_file(101, music_info=info, progress_cb=_boom)
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assert r.success, '进度回调异常绝不影响下载主流程'
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def test_music_info_fetched_when_not_provided(env, monkeypatch):
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dl, _state, install = env
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info = _info(size=20)
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seen: list[tuple] = []
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monkeypatch.setattr(dl, 'get_music_info',
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lambda mid, q, c=None: (seen.append((mid, q)), info)[1])
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install(_body(20))
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r = dl.download_music_file(101, 'lossless')
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assert r.success and seen == [(101, 'lossless')]
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# ============ 缓存校验 ============
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def test_cache_hit_skips_network(env):
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dl, _state, install = env
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info = _info(size=20)
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fp, _ = _paths(dl, info)
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fp.write_bytes(b'c' * 20)
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session = install(lambda *a: pytest.fail('缓存命中不应发网络请求'))
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r = dl.download_music_file(101, music_info=info)
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assert r.success and r.file_size == 20
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assert session.calls == []
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def test_cache_size_mismatch_triggers_redownload(env):
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dl, _state, install = env
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info = _info(size=20)
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fp, _ = _paths(dl, info)
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fp.write_bytes(b'c' * 15) # 与本次期望不符 = 缓存 miss
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session = install(_body(20))
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r = dl.download_music_file(101, music_info=info)
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assert r.success and fp.read_bytes() == b'x' * 20
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assert len(session.calls) == 1, '坏缓存应被删除并重下，而不是当结果交付'
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def test_zero_byte_cache_rejected_when_expected_size_unknown(env):
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dl, _state, install = env
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info = _info(size=0)
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fp, _ = _paths(dl, info)
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fp.write_bytes(b'')
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session = install(lambda a, u, kw: _FakeResponse([b'good']))
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r = dl.download_music_file(101, music_info=info)
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assert r.success and fp.read_bytes() == b'good'
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assert len(session.calls) == 1, '期望未知时至少拒绝 0 字节坏文件'
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# ============ 断点续传 ============
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def test_resume_sends_range_and_appends(env):
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dl, _state, install = env
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info = _info(size=20)
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fp, part = _paths(dl, info)
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part.write_bytes(b'p' * 10)
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session = install(lambda a, u, kw: _FakeResponse(
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[b'q' * 10], status=206, headers={'Content-Range': 'bytes 10-19/20'}))
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seen: list[tuple[int, int]] = []
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r = dl.download_music_file(101, music_info=info,
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progress_cb=lambda w, t: seen.append((w, t)))
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assert r.success
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assert session.calls[0][1]['headers'].get('Range') == 'bytes=10-'
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assert fp.read_bytes() == b'p' * 10 + b'q' * 10, '续传应追加而非覆盖'
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assert seen[0] == (10, 20), '起始进度应带续传起点'
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def test_server_ignoring_range_rewrites_from_zero(env):
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dl, _state, install = env
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info = _info(size=20)
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fp, part = _paths(dl, info)
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part.write_bytes(b'p' * 10)
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install(lambda a, u, kw: _FakeResponse([b'r' * 20], status=200))
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r = dl.download_music_file(101, music_info=info)
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assert r.success and fp.read_bytes() == b'r' * 20, '服务器返回 200 须从头重写'
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def test_complete_part_promoted_without_network(env):
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dl, _state, install = env
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info = _info(size=20)
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fp, part = _paths(dl, info)
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part.write_bytes(b'z' * 20) # 已下完但未改名
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session = install(lambda *a: pytest.fail('完整残片不应发网络请求'))
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r = dl.download_music_file(101, music_info=info)
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assert r.success and r.file_size == 20
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assert session.calls == []
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assert fp.read_bytes() == b'z' * 20 and not part.exists()
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def test_oversized_part_discarded_starts_from_zero(env):
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dl, _state, install = env
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info = _info(size=20)
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_fp, part = _paths(dl, info)
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part.write_bytes(b'o' * 30) # 超尺寸残片没有续传价值
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session = install(_body(20))
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r = dl.download_music_file(101, music_info=info)
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assert r.success
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assert 'Range' not in session.calls[0][1]['headers']
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def test_zero_byte_part_discarded(env):
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dl, _state, install = env
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info = _info(size=20)
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_fp, part = _paths(dl, info)
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part.write_bytes(b'')
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session = install(_body(20))
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r = dl.download_music_file(101, music_info=info)
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assert r.success and 'Range' not in session.calls[0][1]['headers']
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def test_content_range_offset_mismatch_restarts_from_scratch(env):
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dl, _state, install = env
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info = _info(size=20)
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fp, part = _paths(dl, info)
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part.write_bytes(b'p' * 10)
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def responder(n, _url, _kw):
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if n == 1:
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return _FakeResponse([b'q' * 5], status=206,
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headers={'Content-Range': 'bytes 3-7/20'})
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return _FakeResponse([b'f' * 20], status=200)
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session = install(responder)
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r = dl.download_music_file(101, music_info=info, retries=1)
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assert r.success and len(session.calls) == 2
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assert 'Range' not in session.calls[1][1]['headers'], '清残片后应从头下'
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assert fp.read_bytes() == b'f' * 20
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def test_206_without_content_range_restarts_from_scratch(env):
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dl, _state, install = env
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info = _info(size=20)
|
||
_fp, part = _paths(dl, info)
|
||
part.write_bytes(b'p' * 10)
|
||
|
||
def responder(n, _url, _kw):
|
||
if n == 1:
|
||
return _FakeResponse([b'q' * 5], status=206) # 头被中间层剥离
|
||
return _FakeResponse([b'f' * 20], status=200)
|
||
|
||
session = install(responder)
|
||
|
||
r = dl.download_music_file(101, music_info=info, retries=1)
|
||
|
||
assert r.success and len(session.calls) == 2
|
||
assert 'Range' not in session.calls[1][1]['headers']
|
||
|
||
|
||
def test_http_416_restarts_from_scratch(env):
|
||
dl, _state, install = env
|
||
info = _info(size=20)
|
||
fp, part = _paths(dl, info)
|
||
part.write_bytes(b'p' * 10)
|
||
|
||
def responder(n, _url, _kw):
|
||
if n == 1:
|
||
return _FakeResponse([], status=416)
|
||
return _FakeResponse([b'f' * 20], status=200)
|
||
|
||
session = install(responder)
|
||
|
||
r = dl.download_music_file(101, music_info=info, retries=1)
|
||
|
||
assert r.success and len(session.calls) == 2
|
||
assert 'Range' not in session.calls[1][1]['headers']
|
||
assert fp.read_bytes() == b'f' * 20
|
||
|
||
|
||
# ============ 失败与重试 ============
|
||
|
||
|
||
def test_cdn_4xx_is_deterministic_and_not_retried(env):
|
||
dl, _state, install = env
|
||
info = _info(size=20)
|
||
session = install(lambda a, u, kw: _FakeResponse([], status=403))
|
||
|
||
with pytest.raises(DownloadException) as ei:
|
||
dl.download_music_file(101, music_info=info, retries=2)
|
||
|
||
assert 'HTTP 403' in str(ei.value)
|
||
assert len(session.calls) == 1, '确定性失败对同一失效直链白重试毫无意义'
|
||
|
||
|
||
def test_408_is_retried_then_reported_as_failure(env):
|
||
dl, _state, install = env
|
||
info = _info(size=20)
|
||
session = install(lambda a, u, kw: _FakeResponse([], status=408))
|
||
|
||
r = dl.download_music_file(101, music_info=info, retries=1)
|
||
|
||
assert not r.success
|
||
assert '下载请求失败' in r.error_message
|
||
assert len(session.calls) == 2, '408 请求超时应保留可重试'
|
||
|
||
|
||
def test_5xx_is_retried_and_keeps_part(env):
|
||
"""5xx 是服务端瞬时故障（非确定性失败）：应可重试，且保留 .part 供续传。
|
||
|
||
与 4xx 的分界在这里钉住：error 分类只看 400<=status<500，5xx 落回裸重抛，
|
||
由外层 RequestException 分支退避重试。此前这条路径无测试覆盖。
|
||
"""
|
||
dl, _state, install = env
|
||
info = _info(size=100)
|
||
fp, part = _paths(dl, info)
|
||
part.write_bytes(b'p' * 10)
|
||
session = install(lambda a, u, kw: _FakeResponse([], status=500))
|
||
|
||
r = dl.download_music_file(101, music_info=info, retries=1)
|
||
|
||
assert not r.success and '下载请求失败' in r.error_message
|
||
assert len(session.calls) == 2, '5xx 非确定性失败，应重试'
|
||
assert not fp.exists(), '未交付不得留下最终文件'
|
||
assert part.stat().st_size == 10, '.part 应保留供下轮续传'
|
||
|
||
|
||
def test_incomplete_size_keeps_part_and_reports(env):
|
||
dl, _state, install = env
|
||
info = _info(size=100)
|
||
fp, part = _paths(dl, info)
|
||
install(_body(10))
|
||
|
||
r = dl.download_music_file(101, music_info=info, retries=0)
|
||
|
||
assert not r.success and '下载不完整' in r.error_message
|
||
assert part.exists() and part.stat().st_size == 10, '.part 应保留以供续传'
|
||
assert not fp.exists(), '不完整的下载不得转正交付'
|
||
|
||
|
||
def test_incomplete_then_resumes_on_next_attempt(env):
|
||
dl, _state, install = env
|
||
info = _info(size=100)
|
||
_fp, part = _paths(dl, info)
|
||
|
||
def responder(n, _url, _kw):
|
||
if n == 1:
|
||
return _FakeResponse([b'a' * 10], status=200)
|
||
return _FakeResponse([b'b' * 5], status=206,
|
||
headers={'Content-Range': 'bytes 10-14/100'})
|
||
|
||
session = install(responder)
|
||
|
||
r = dl.download_music_file(101, music_info=info, retries=1)
|
||
|
||
assert not r.success and '下载不完整' in r.error_message
|
||
assert session.calls[1][1]['headers'].get('Range') == 'bytes=10-', '下轮应续传'
|
||
assert part.stat().st_size == 15
|
||
|
||
|
||
def test_network_error_keeps_part_for_resume(env):
|
||
dl, _state, install = env
|
||
info = _info(size=100)
|
||
fp, part = _paths(dl, info)
|
||
|
||
def chunks():
|
||
yield b'a' * 10
|
||
raise sync_http.RequestException('连接中断')
|
||
|
||
install(lambda a, u, kw: _FakeResponse(chunks()))
|
||
|
||
r = dl.download_music_file(101, music_info=info, retries=0)
|
||
|
||
assert not r.success and '下载请求失败' in r.error_message
|
||
assert part.exists() and part.stat().st_size == 10, '网络错误应保留 .part'
|
||
assert not fp.exists()
|
||
|
||
|
||
# ============ 内容校验与体积上限 ============
|
||
|
||
|
||
def test_unknown_size_non_audio_content_rejected(env):
|
||
dl, state, install = env
|
||
info = _info(size=0)
|
||
fp, part = _paths(dl, info)
|
||
state['sniff'] = False
|
||
install(lambda a, u, kw: _FakeResponse([b'<html>blocked</html>']))
|
||
|
||
with pytest.raises(DownloadException) as ei:
|
||
dl.download_music_file(101, music_info=info)
|
||
|
||
assert '非音频数据' in str(ei.value)
|
||
assert not part.exists() and not fp.exists()
|
||
|
||
|
||
def test_unknown_size_audio_content_accepted(env):
|
||
dl, state, install = env
|
||
info = _info(size=0)
|
||
fp, _ = _paths(dl, info)
|
||
state['sniff'] = True
|
||
install(lambda a, u, kw: _FakeResponse([b'ID3audio']))
|
||
|
||
r = dl.download_music_file(101, music_info=info)
|
||
|
||
assert r.success and fp.read_bytes() == b'ID3audio'
|
||
|
||
|
||
def test_size_limit_discards_part_and_fails(env, monkeypatch):
|
||
dl, _state, install = env
|
||
monkeypatch.setattr('music_downloader.downloader._MAX_DOWNLOAD_BYTES', 16)
|
||
info = _info(size=0)
|
||
fp, part = _paths(dl, info)
|
||
install(lambda a, u, kw: _FakeResponse([b'x' * 100]))
|
||
|
||
with pytest.raises(DownloadException) as ei:
|
||
dl.download_music_file(101, music_info=info)
|
||
|
||
assert '大小上限' in str(ei.value)
|
||
assert not part.exists() and not fp.exists(), '超限残片无续传价值，须清理'
|
||
|
||
|
||
# ============ 取消 ============
|
||
|
||
|
||
def test_cancel_before_transfer_clears_part_and_skips_network(env):
|
||
dl, _state, install = env
|
||
info = _info(size=20)
|
||
_fp, part = _paths(dl, info)
|
||
part.write_bytes(b'p' * 5)
|
||
cancel = threading.Event()
|
||
cancel.set()
|
||
session = install(lambda *a: pytest.fail('已取消不应发网络请求'))
|
||
|
||
with pytest.raises(DownloadCanceled):
|
||
dl.download_music_file(101, music_info=info, cancel_event=cancel)
|
||
|
||
assert session.calls == []
|
||
assert not part.exists(), '取消须清掉 .part'
|
||
|
||
|
||
def test_cancel_midway_clears_half_written_file(env):
|
||
dl, _state, install = env
|
||
info = _info(size=20)
|
||
fp, part = _paths(dl, info)
|
||
cancel = threading.Event()
|
||
|
||
def chunks():
|
||
yield b'a' * 5
|
||
cancel.set()
|
||
yield b'b' * 15
|
||
|
||
install(lambda a, u, kw: _FakeResponse(chunks()))
|
||
|
||
with pytest.raises(DownloadCanceled):
|
||
dl.download_music_file(101, music_info=info, cancel_event=cancel)
|
||
|
||
assert not part.exists() and not fp.exists()
|
||
|
||
|
||
def test_network_error_while_canceled_reports_canceled(env):
|
||
dl, _state, install = env
|
||
info = _info(size=20)
|
||
fp, part = _paths(dl, info)
|
||
cancel = threading.Event()
|
||
|
||
def chunks():
|
||
yield b'a' * 5
|
||
cancel.set()
|
||
raise OSError('句柄异常')
|
||
|
||
install(lambda a, u, kw: _FakeResponse(chunks()))
|
||
|
||
with pytest.raises(DownloadCanceled):
|
||
dl.download_music_file(101, music_info=info, cancel_event=cancel, retries=2)
|
||
|
||
assert not part.exists() and not fp.exists(), '已取消时残片没有续传价值'
|
||
|
||
|
||
def test_cancel_after_promote_keeps_file_but_skips_metadata(env):
|
||
dl, state, install = env
|
||
info = _info(size=20)
|
||
fp, part = _paths(dl, info)
|
||
cancel = threading.Event()
|
||
|
||
def cb(written, _total):
|
||
if written >= 20:
|
||
cancel.set()
|
||
|
||
install(_body(20))
|
||
|
||
with pytest.raises(DownloadCanceled):
|
||
dl.download_music_file(101, music_info=info, cancel_event=cancel,
|
||
progress_cb=cb)
|
||
|
||
assert fp.exists() and not part.exists(), '已转正的文件不回滚'
|
||
assert state['meta'] == [], '取消后不应再写元数据'
|
||
|
||
|
||
# ============ 元数据 ============
|
||
|
||
|
||
def test_metadata_written_only_when_requested(env):
|
||
dl, state, install = env
|
||
install(_body(20))
|
||
|
||
dl.download_music_file(101, music_info=_info(mid=101), write_meta=False)
|
||
assert state['meta'] == [], 'write_meta=False 不应写元数据'
|
||
|
||
r = dl.download_music_file(102, music_info=_info(mid=102), write_meta=True,
|
||
meta_fields=['title'])
|
||
assert r.success
|
||
assert [f for _p, f in state['meta']] == [['title']], 'fields 应原样透传'
|