Cin's review note: typing artist_name as plain `str` forced callers
that didn't have a name to pass `""` as a placeholder, which leaks the
parameter's emptiness contract into every call site and reads badly in
tests. Switching to `Optional[str] = None` lets callers omit it.
The function body's `if artist_name and active_server:` check already
handles None and "" identically, so no body changes were needed. Tests
that previously passed `artist_name=""` drop the argument; one new test
covers the omitted-arg path explicitly.
The web_server.py wrapper takes the same default for symmetry.
Cin pointed out that the prior version of test_artist_source_lookup.py
AST-parsed web_server.py to verify a constant and to string-match a
function's response keys. That was a workaround for the fact that
web_server.py can't be imported at test time (it boots Spotify,
Soulseek, Plex, etc.) — the right answer is to move the logic into a
side-effect-free module so it can be imported and tested directly.
This commit:
- adds core/artist_source_lookup.py containing the SOURCE_ID_FIELD
map, the SOURCE_ONLY_ARTIST_SOURCES set, and find_library_artist_for_source
- replaces the inline definitions in web_server.py with imports +
a thin wrapper that injects the active media server
- rewrites the tests to import from the core module directly:
* mapping correctness is now a plain equality assertion
* lookup behaviour is exercised against a real MusicDatabase
* the AST parse and the string-matching contract test class are
gone
- drops the _build_source_only_artist_detail contract test entirely
(the weakest of the four — it was just string-matching the function
body); when that function moves to core/ it can get a real
behavioural test alongside.
Test runtime drops from ~161s to ~5.8s. All 18 tests pass.
Four targeted backend tests for behaviour added during the Search/Artists
unification work:
1. _SOURCE_ID_FIELD mapping is parsed out of web_server.py via AST and
compared against an explicit expectation, so silent renames break the
test instead of silently breaking library-upgrade detection.
2. Every column in _SOURCE_ID_FIELD must exist on the real artists table
after migrations run. This is the schema-vs-query contract that the
`deezer_artist_id` typo would have failed instantly.
3. The two queries from the watchlist-config enrichment path execute
verbatim against a fresh DB — separate ones for the artists table
(deezer_id / discogs_id) and the watchlist_artists join (deezer_artist_id).
Documents the column-name split that caused the original bug.
4. Static contract test for _build_source_only_artist_detail's response
shape: every JSON key the frontend reads (success/artist/discography/
image_url/server_source/genres/lastfm_*) must appear in the function
source, plus the dynamic source-id stamp and the dedup_variants=False
opt-out.
Plus a behavioural test for MetadataLookupOptions.dedup_variants=False
in test_metadata_service_discography.py — proves the flag actually keeps
variant releases that get_artist_detail_discography would otherwise
collapse to a single canonical entry.
