fix: surface empty OHLCV fetch as a warning, not success

Fetching a symbol the provider doesn't cover (e.g. RHM/Rheinmetall — Alpaca
serves US listings only) returned 0 bars but reported "complete · Successfully
ingested 0 records", which the UI showed as green success.

fetch_and_ingest now returns a distinct `no_data` status when the provider
returns nothing AND the ticker has no history (vs. "already up to date" when bars
exist). The fetch endpoint maps it to a `warning` source status, and the fetch
toast renders it as ⚠ with the provider message instead of success.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/unit/test_ingestion_service.py

@@ -0,0 +1,62 @@
+"""Tests for the ingestion service — honest reporting of empty provider fetches."""
+
+from __future__ import annotations
+
+from datetime import date, timedelta
+
+import pytest
+
+from app.models.ticker import Ticker
+from app.providers.protocol import OHLCVData
+from app.services import ingestion_service as svc
+from tests.conftest import MockMarketDataProvider, _test_session_factory  # type: ignore
+
+
+@pytest.fixture
+async def session():
+    async with _test_session_factory() as s:
+        yield s
+
+
+async def _add_ticker(session, symbol: str) -> None:
+    session.add(Ticker(symbol=symbol))
+    await session.commit()
+
+
+def _bars(symbol: str, n: int) -> list[OHLCVData]:
+    today = date.today()
+    return [
+        OHLCVData(ticker=symbol, date=today - timedelta(days=i),
+                  open=100.0, high=101.0, low=99.0, close=100.0, volume=1000)
+        for i in range(n)
+    ]
+
+
+async def test_empty_fetch_on_new_ticker_reports_no_data(session):
+    # A non-US symbol (e.g. RHM/Rheinmetall) Alpaca doesn't cover → empty bars.
+    # This must NOT report success; it surfaces as no_data.
+    await _add_ticker(session, "RHM")
+    result = await svc.fetch_and_ingest(session, MockMarketDataProvider(ohlcv_data=[]), "RHM")
+
+    assert result.status == "no_data"
+    assert result.records_ingested == 0
+    assert "provider" in (result.message or "").lower()
+
+
+async def test_happy_path_ingests_bars(session):
+    await _add_ticker(session, "AAA")
+    result = await svc.fetch_and_ingest(session, MockMarketDataProvider(ohlcv_data=_bars("AAA", 3)), "AAA")
+
+    assert result.status == "complete"
+    assert result.records_ingested == 3
+
+
+async def test_empty_fetch_with_existing_history_is_up_to_date(session):
+    # Covered ticker, just no new bars in the window → complete, not no_data.
+    await _add_ticker(session, "BBB")
+    await svc.fetch_and_ingest(session, MockMarketDataProvider(ohlcv_data=_bars("BBB", 2)), "BBB")
+
+    result = await svc.fetch_and_ingest(session, MockMarketDataProvider(ohlcv_data=[]), "BBB")
+
+    assert result.status == "complete"
+    assert result.records_ingested == 0