soulsync/tests/downloads/test_download_engine.py
Broque Thomas badb5dd7de B2: Engine owns cross-source query dispatch
`DownloadEngine` grows async query methods that wrap plugin
iteration: `get_all_downloads` (concatenates every plugin's
active downloads), `get_download_status` (first plugin to
recognize the id wins), `cancel_download` (with source-hint
routing — streaming sources go direct, unknown hints route to
Soulseek as peer username), and `clear_all_completed_downloads`
(skips unconfigured plugins).

Code moved from the orchestrator's hand-iterated loops into the
engine. Orchestrator delegation comes in B3 — for B2 the engine
methods exist but nothing calls them yet.

Per-plugin behavior preserved verbatim (defensive `try ... except`
swallows per-iteration, unconfigured-skip on clear, source-hint
routing semantics). Phase A pinning tests + 8 new engine query
tests catch any drift.

Pure additive — zero behavior change for users.
2026-05-04 12:42:15 -07:00

389 lines
14 KiB
Python

"""Tests for the DownloadEngine skeleton (Phase B).
Pinning the engine's state-storage contract: add/update/remove,
per-source iteration, find-by-id, plugin registration, lock-held
mutations vs lock-released reads. Future phases (C/D/E/F) bolt
behavior on top of this surface — these tests stay green and act
as the regression net while behavior moves in.
"""
from __future__ import annotations
import threading
import pytest
from core.download_engine import DownloadEngine
# ---------------------------------------------------------------------------
# Plugin registration
# ---------------------------------------------------------------------------
def test_register_plugin_stores_under_source_name():
engine = DownloadEngine()
plugin = object()
engine.register_plugin('soulseek', plugin)
assert engine.get_plugin('soulseek') is plugin
assert 'soulseek' in engine.registered_sources()
def test_get_plugin_returns_none_for_unknown_source():
engine = DownloadEngine()
assert engine.get_plugin('made_up') is None
def test_register_plugin_overwrites_on_duplicate(caplog):
"""Re-registering under the same name overwrites and warns. Not a
common path but useful so test fixtures that build a fresh engine
can swap a mock plugin in without setup gymnastics."""
engine = DownloadEngine()
first = object()
second = object()
engine.register_plugin('soulseek', first)
engine.register_plugin('soulseek', second)
assert engine.get_plugin('soulseek') is second
# ---------------------------------------------------------------------------
# Active-download state — add / get / update / remove
# ---------------------------------------------------------------------------
def test_add_record_inserts_under_composite_key():
engine = DownloadEngine()
engine.add_record('youtube', 'dl-1', {'state': 'Initializing', 'progress': 0.0})
rec = engine.get_record('youtube', 'dl-1')
assert rec is not None
assert rec['state'] == 'Initializing'
assert rec['progress'] == 0.0
def test_get_record_returns_shallow_copy():
"""Mutating the returned dict must NOT affect engine state.
Engine reads should be safe to hold / iterate without locks."""
engine = DownloadEngine()
engine.add_record('youtube', 'dl-1', {'state': 'Initializing'})
rec = engine.get_record('youtube', 'dl-1')
rec['state'] = 'TamperedByCaller'
# Engine state still has the original.
fresh = engine.get_record('youtube', 'dl-1')
assert fresh['state'] == 'Initializing'
def test_update_record_applies_partial_patch():
engine = DownloadEngine()
engine.add_record('tidal', 'dl-2', {'state': 'Initializing', 'progress': 0.0,
'file_path': None})
engine.update_record('tidal', 'dl-2', {'state': 'Completed, Succeeded',
'progress': 100.0,
'file_path': '/tmp/song.flac'})
rec = engine.get_record('tidal', 'dl-2')
assert rec['state'] == 'Completed, Succeeded'
assert rec['progress'] == 100.0
assert rec['file_path'] == '/tmp/song.flac'
def test_update_record_is_noop_when_record_removed():
"""If a record was removed (e.g. user cancelled mid-download),
the worker thread's late update is silently dropped — never
raises. Mirrors the per-client `if download_id in active_downloads`
guard pattern that's all over the existing clients."""
engine = DownloadEngine()
engine.add_record('tidal', 'dl-2', {'state': 'Initializing'})
engine.remove_record('tidal', 'dl-2')
# Should not raise.
engine.update_record('tidal', 'dl-2', {'state': 'Completed, Succeeded'})
assert engine.get_record('tidal', 'dl-2') is None
def test_remove_record_returns_removed_record():
engine = DownloadEngine()
engine.add_record('qobuz', 'dl-3', {'state': 'InProgress'})
removed = engine.remove_record('qobuz', 'dl-3')
assert removed is not None
assert removed['state'] == 'InProgress'
assert engine.get_record('qobuz', 'dl-3') is None
def test_remove_record_returns_none_when_missing():
engine = DownloadEngine()
assert engine.remove_record('qobuz', 'never-existed') is None
# ---------------------------------------------------------------------------
# Iteration
# ---------------------------------------------------------------------------
def test_iter_records_for_source_filters_correctly():
engine = DownloadEngine()
engine.add_record('youtube', 'yt-1', {'title': 'A'})
engine.add_record('youtube', 'yt-2', {'title': 'B'})
engine.add_record('tidal', 'td-1', {'title': 'C'})
yt_records = list(engine.iter_records_for_source('youtube'))
assert len(yt_records) == 2
assert {r['title'] for r in yt_records} == {'A', 'B'}
td_records = list(engine.iter_records_for_source('tidal'))
assert len(td_records) == 1
assert td_records[0]['title'] == 'C'
def test_iter_all_records_yields_source_paired_with_record():
engine = DownloadEngine()
engine.add_record('youtube', 'yt-1', {'title': 'A'})
engine.add_record('tidal', 'td-1', {'title': 'B'})
pairs = list(engine.iter_all_records())
assert len(pairs) == 2
sources = {source for source, _ in pairs}
titles = {record['title'] for _, record in pairs}
assert sources == {'youtube', 'tidal'}
assert titles == {'A', 'B'}
def test_iter_yields_shallow_copies():
"""Iteration returns COPIES — caller can hold the list and mutate
each record without affecting engine state. Important: future
Phase B3's `get_all_downloads` will iterate then build
DownloadStatus objects from the snapshots."""
engine = DownloadEngine()
engine.add_record('youtube', 'yt-1', {'title': 'A'})
snapshot = list(engine.iter_records_for_source('youtube'))
snapshot[0]['title'] = 'TAMPERED'
fresh = engine.get_record('youtube', 'yt-1')
assert fresh['title'] == 'A'
# ---------------------------------------------------------------------------
# find_record — id-only lookup
# ---------------------------------------------------------------------------
def test_find_record_returns_source_and_copy():
engine = DownloadEngine()
engine.add_record('youtube', 'shared-id-shape', {'title': 'A'})
result = engine.find_record('shared-id-shape')
assert result is not None
source, record = result
assert source == 'youtube'
assert record['title'] == 'A'
def test_find_record_returns_none_for_unknown_id():
engine = DownloadEngine()
engine.add_record('youtube', 'yt-1', {})
assert engine.find_record('nonexistent') is None
# ---------------------------------------------------------------------------
# Thread safety — basic concurrent-mutation smoke
# ---------------------------------------------------------------------------
def test_concurrent_adds_dont_lose_records():
"""Hammer the engine with concurrent add_record from multiple
threads. With proper locking, every record lands in state.
Future Phase C BackgroundDownloadWorker spawns N threads doing
exactly this kind of mutation."""
engine = DownloadEngine()
def add_records(source, base):
for i in range(50):
engine.add_record(source, f'{base}-{i}', {'i': i})
threads = [
threading.Thread(target=add_records, args=(f'src-{n}', f'dl-{n}'))
for n in range(4)
]
for t in threads:
t.start()
for t in threads:
t.join()
total = sum(1 for _ in engine.iter_all_records())
assert total == 4 * 50 # 200 records, none lost
# ---------------------------------------------------------------------------
# Cross-source query dispatch (Phase B2)
# ---------------------------------------------------------------------------
def _run_async(coro):
import asyncio
loop = asyncio.new_event_loop()
try:
return loop.run_until_complete(coro)
finally:
loop.close()
class _FakePlugin:
"""Minimal plugin double for engine query tests. Exposes the
methods engine.get_all_downloads / get_download_status /
cancel_download / clear_all_completed_downloads call."""
def __init__(self, name, configured=True, downloads=None,
cancel_result=True, clear_result=True):
self.name = name
self._configured = configured
self._downloads = downloads or []
self._cancel_result = cancel_result
self._clear_result = clear_result
self.cancel_calls = []
self.clear_calls = 0
def is_configured(self):
return self._configured
async def get_all_downloads(self):
return list(self._downloads)
async def get_download_status(self, download_id):
for d in self._downloads:
if getattr(d, 'id', None) == download_id:
return d
return None
async def cancel_download(self, download_id, source_hint, remove):
self.cancel_calls.append((download_id, source_hint, remove))
return self._cancel_result
async def clear_all_completed_downloads(self):
self.clear_calls += 1
return self._clear_result
class _FakeStatus:
def __init__(self, id, source):
self.id = id
self.source = source
def test_engine_get_all_downloads_aggregates_across_plugins():
"""Engine concatenates every plugin's get_all_downloads output —
same behavior as the legacy orchestrator."""
engine = DownloadEngine()
yt_plugin = _FakePlugin('youtube', downloads=[_FakeStatus('yt-1', 'youtube')])
td_plugin = _FakePlugin('tidal', downloads=[_FakeStatus('td-1', 'tidal'),
_FakeStatus('td-2', 'tidal')])
engine.register_plugin('youtube', yt_plugin)
engine.register_plugin('tidal', td_plugin)
result = _run_async(engine.get_all_downloads())
assert len(result) == 3
assert {r.id for r in result} == {'yt-1', 'td-1', 'td-2'}
def test_engine_get_all_downloads_swallows_per_plugin_exceptions():
"""One plugin throwing must NOT take down the whole list — same
defensive behavior as the legacy orchestrator (matched by
`try ... except: pass` on every iteration)."""
engine = DownloadEngine()
class _BrokenPlugin:
async def get_all_downloads(self):
raise RuntimeError("boom")
yt_plugin = _FakePlugin('youtube', downloads=[_FakeStatus('yt-1', 'youtube')])
engine.register_plugin('broken', _BrokenPlugin())
engine.register_plugin('youtube', yt_plugin)
result = _run_async(engine.get_all_downloads())
assert [r.id for r in result] == ['yt-1']
def test_engine_get_download_status_returns_first_match():
engine = DownloadEngine()
yt_plugin = _FakePlugin('youtube', downloads=[_FakeStatus('shared', 'youtube')])
td_plugin = _FakePlugin('tidal', downloads=[])
engine.register_plugin('youtube', yt_plugin)
engine.register_plugin('tidal', td_plugin)
result = _run_async(engine.get_download_status('shared'))
assert result is not None
assert result.id == 'shared'
def test_engine_cancel_routes_streaming_source_directly():
"""When source_hint is a known streaming-source name (not
'soulseek'), engine routes the cancel to that specific plugin
only — doesn't ask every other plugin first."""
engine = DownloadEngine()
yt_plugin = _FakePlugin('youtube')
td_plugin = _FakePlugin('tidal')
engine.register_plugin('youtube', yt_plugin)
engine.register_plugin('tidal', td_plugin)
_run_async(engine.cancel_download('dl-1', 'tidal', remove=False))
assert yt_plugin.cancel_calls == []
assert td_plugin.cancel_calls == [('dl-1', 'tidal', False)]
def test_engine_cancel_routes_unknown_source_hint_to_soulseek():
"""A username that's NOT in the plugin registry is a real
Soulseek peer name — route to the soulseek plugin."""
engine = DownloadEngine()
sl_plugin = _FakePlugin('soulseek')
yt_plugin = _FakePlugin('youtube')
engine.register_plugin('soulseek', sl_plugin)
engine.register_plugin('youtube', yt_plugin)
_run_async(engine.cancel_download('dl-1', 'random_peer_username', remove=False))
assert sl_plugin.cancel_calls == [('dl-1', 'random_peer_username', False)]
assert yt_plugin.cancel_calls == []
def test_engine_cancel_falls_back_to_iterating_all_plugins_without_hint():
"""No source hint → ask every plugin until one accepts the
cancel (returns True). Mirrors legacy orchestrator behavior."""
engine = DownloadEngine()
yt_plugin = _FakePlugin('youtube', cancel_result=False)
td_plugin = _FakePlugin('tidal', cancel_result=True)
engine.register_plugin('youtube', yt_plugin)
engine.register_plugin('tidal', td_plugin)
result = _run_async(engine.cancel_download('dl-1', None, remove=False))
assert result is True
# Both plugins were asked; tidal accepted.
assert len(yt_plugin.cancel_calls) == 1
assert len(td_plugin.cancel_calls) == 1
def test_engine_clear_all_skips_unconfigured_plugins():
"""Unconfigured plugins are silently skipped (no API call, no
error) — matches legacy orchestrator's defensive handling."""
engine = DownloadEngine()
configured = _FakePlugin('youtube', configured=True, clear_result=True)
unconfigured = _FakePlugin('tidal', configured=False)
engine.register_plugin('youtube', configured)
engine.register_plugin('tidal', unconfigured)
result = _run_async(engine.clear_all_completed_downloads())
assert result is True
assert configured.clear_calls == 1
assert unconfigured.clear_calls == 0
def test_engine_clear_all_returns_false_when_any_configured_plugin_fails():
engine = DownloadEngine()
failing = _FakePlugin('youtube', configured=True, clear_result=False)
engine.register_plugin('youtube', failing)
result = _run_async(engine.clear_all_completed_downloads())
assert result is False