feat: orchestrate grounded recommendations

backend/tests/test_orchestrator.py

@@ -0,0 +1,245 @@
+"""End-to-end pipeline tests using deterministic service fakes."""
+
+import asyncio
+from collections.abc import AsyncGenerator
+
+from app.config import Settings
+from app.domain.models import (
+    ConversationTurn,
+    Familiarity,
+    Intent,
+    PreviousRecommendation,
+    RerankSelection,
+    Track,
+    TrackCandidate,
+)
+from app.pipeline.event import PipelineEvent, PipelineTrackEvent
+from app.pipeline.orchestrator import RecommendationPipeline
+from app.ports.protocols import RecommenderOutputError, TimeRange
+
+
+class FakeCatalog:
+    """Return exact tracks and a configurable known-track sample."""
+
+    def __init__(self, tracks: tuple[Track, ...], known_tracks: tuple[Track, ...] = ()) -> None:
+        """Index tracks by title and expose taste-call counters."""
+        self.tracks_by_title = {track.title: track for track in tracks}
+        self.known_tracks = known_tracks
+        self.search_call_count = 0
+        self.taste_call_count = 0
+
+    async def search_tracks(self, query: str, limit: int = 10) -> list[Track]:
+        """Resolve an exact fielded title and miss bare fallbacks."""
+        self.search_call_count += 1
+        if 'track:"' not in query:
+            return []
+        title = query.split('track:"', 1)[1].split('"', 1)[0]
+        track = self.tracks_by_title.get(title)
+        return [track] if track is not None else []
+
+    async def fetch_top_artists(self, time_range: TimeRange, limit: int) -> list[str]:
+        """Return one stable taste artist."""
+        self.taste_call_count += 1
+        return ["Taste Artist"]
+
+    async def fetch_top_tracks(self, time_range: TimeRange, limit: int) -> list[Track]:
+        """Return no top tracks."""
+        self.taste_call_count += 1
+        return []
+
+    async def fetch_saved_tracks(self, limit: int) -> list[Track]:
+        """Return the configured known tracks."""
+        self.taste_call_count += 1
+        return list(self.known_tracks)
+
+
+class FakeRecommender:
+    """Return fixed intents and either selections or structured failures."""
+
+    def __init__(
+        self,
+        intents: list[Intent],
+        selection_ids: tuple[str, ...] = (),
+        failure_count: int = 0,
+    ) -> None:
+        """Store deterministic outputs for successive calls."""
+        self.intents = intents
+        self.selection_ids = selection_ids
+        self.failure_count = failure_count
+        self.rerank_call_count = 0
+
+    async def create_intent(
+        self,
+        query: str,
+        history: tuple[ConversationTurn, ...],
+        previous_recommendations: tuple[PreviousRecommendation, ...],
+        taste_summary: str,
+        candidate_count: int,
+    ) -> Intent:
+        """Return the next fixed intent."""
+        return self.intents.pop(0)
+
+    async def stream_rerank(
+        self,
+        intent: Intent,
+        grounded_tracks: tuple[Track, ...],
+        taste_summary: str,
+        history: tuple[ConversationTurn, ...],
+        selection_count: int,
+        correction: str | None = None,
+    ) -> AsyncGenerator[RerankSelection]:
+        """Stream configured ids or fail before yielding."""
+        self.rerank_call_count += 1
+        if self.failure_count:
+            self.failure_count -= 1
+            raise RecommenderOutputError("invalid test output")
+        selected_ids = self.selection_ids or tuple(track.id for track in grounded_tracks)
+        for track_id in selected_ids[:selection_count]:
+            yield RerankSelection(track_id, f"Reason for {track_id}")
+
+
+def test_event_order_and_rerank_ids_stay_inside_grounded_pool() -> None:
+    async def run() -> None:
+        first = _track("first", "First Song")
+        second = _track("second", "Second Song")
+        catalog = FakeCatalog((first, second))
+        recommender = FakeRecommender([_intent(first, second)], ("second", "first"))
+
+        events = await _run_pipeline(catalog, recommender)
+
+        assert [event.type for event in events] == ["metadata", "track", "track", "done"]
+        track_events = [event for event in events if isinstance(event, PipelineTrackEvent)]
+        assert [event.track.id for event in track_events] == ["second", "first"]
+        assert {event.track.id for event in track_events} <= {"first", "second"}
+
+    asyncio.run(run())
+
+
+def test_rerank_fallback_warns_then_streams_grounded_order() -> None:
+    async def run() -> None:
+        first = _track("first", "First Song")
+        second = _track("second", "Second Song")
+        catalog = FakeCatalog((first, second))
+        recommender = FakeRecommender([_intent(first, second)], failure_count=2)
+
+        events = await _run_pipeline(catalog, recommender)
+
+        assert [event.type for event in events] == [
+            "metadata",
+            "warning",
+            "track",
+            "track",
+            "done",
+        ]
+        assert recommender.rerank_call_count == 2
+        track_events = [event for event in events if isinstance(event, PipelineTrackEvent)]
+        assert [event.track.id for event in track_events] == ["first", "second"]
+
+    asyncio.run(run())
+
+
+def test_new_familiarity_excludes_known_track_ids() -> None:
+    async def run() -> None:
+        known = _track("known", "Known Song")
+        new = _track("new", "New Song")
+        catalog = FakeCatalog((known, new), known_tracks=(known,))
+        intent = _intent(known, new, familiarity=Familiarity.NEW)
+        recommender = FakeRecommender([intent])
+
+        events = await _run_pipeline(catalog, recommender, rerank_count=1)
+
+        track_events = [event for event in events if isinstance(event, PipelineTrackEvent)]
+        assert [event.track.id for event in track_events] == ["new"]
+
+    asyncio.run(run())
+
+
+def test_refinement_reuses_last_grounded_pool_and_cached_taste() -> None:
+    async def run() -> None:
+        track = _track("first", "First Song")
+        initial = _intent(track)
+        refinement = _intent(track, is_refinement=True)
+        catalog = FakeCatalog((track,))
+        recommender = FakeRecommender([initial, refinement])
+        pipeline = _pipeline(recommender, rerank_count=1)
+
+        await _collect(pipeline, catalog, "first request")
+        initial_search_calls = catalog.search_call_count
+        initial_taste_calls = catalog.taste_call_count
+        await _collect(pipeline, catalog, "refine it")
+
+        assert catalog.search_call_count == initial_search_calls
+        assert catalog.taste_call_count == initial_taste_calls
+
+    asyncio.run(run())
+
+
+async def _run_pipeline(
+    catalog: FakeCatalog,
+    recommender: FakeRecommender,
+    rerank_count: int = 2,
+) -> list[PipelineEvent]:
+    return await _collect(_pipeline(recommender, rerank_count=rerank_count), catalog, "query")
+
+
+def _pipeline(recommender: FakeRecommender, rerank_count: int) -> RecommendationPipeline:
+    return RecommendationPipeline(
+        recommender,
+        Settings(
+            rerank_count=rerank_count,
+            rerank_pool_buffer=0,
+            grounding_floor=1,
+            grounding_concurrency=2,
+            request_deadline_seconds=1.0,
+        ),
+    )
+
+
+async def _collect(
+    pipeline: RecommendationPipeline,
+    catalog: FakeCatalog,
+    query: str,
+) -> list[PipelineEvent]:
+    return [
+        event
+        async for event in pipeline.stream(
+            "session",
+            "request",
+            catalog,
+            query,
+            (),
+            (),
+        )
+    ]
+
+
+def _intent(
+    *tracks: Track,
+    familiarity: Familiarity = Familiarity.MIX,
+    is_refinement: bool = False,
+) -> Intent:
+    return Intent(
+        mood=("focused",),
+        activity=None,
+        era=(),
+        languages=(),
+        genres=("electronic",),
+        familiarity=familiarity,
+        is_refinement=is_refinement,
+        intent_summary="Focused electronic discovery.",
+        candidates=tuple(
+            TrackCandidate(title=track.title, artist=track.artists[0]) for track in tracks
+        ),
+    )
+
+
+def _track(track_id: str, title: str) -> Track:
+    return Track(
+        id=track_id,
+        uri=f"spotify:track:{track_id}",
+        title=title,
+        artists=("Artist",),
+        album_name="Album",
+        album_art_url=None,
+        external_url=None,
+    )