analyse: thread user.lang into the system prompt

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/test_localization_integration.py

@@ -176,3 +176,77 @@ async def test_log_translation_fanout_per_language_failure_isolated(tmp_path, mo
     async with factory() as session:
         rows = (await session.execute(select(StrategicLogTranslation))).scalars().all()
     assert rows == []
+
+
+@pytest.mark.asyncio
+async def test_analyse_threads_lang_into_system_prompt(tmp_path, monkeypatch):
+    """When lang='it', the system prompt sent to call_llm contains
+    'Respond in Italian.' — the LLM does the rest."""
+    from app.services import portfolio_analysis as pa
+    from app.services.openrouter import LogResult
+
+    captured = {}
+
+    async def _fake_call_llm(client, messages, **kw):
+        captured["messages"] = messages
+        return LogResult(
+            content="Analisi del portafoglio in italiano.",
+            model="m", prompt_tokens=400, completion_tokens=100, cost_usd=0.0001,
+        )
+    monkeypatch.setattr(pa, "call_llm", _fake_call_llm)
+
+    _, factory, setup = _build_session_factory(tmp_path)
+    await setup()
+
+    payload = {
+        "positions": [{"yahoo_ticker": "AAPL", "qty": 10, "avg_cost": 150.0,
+                       "currency": "USD", "name": "Apple Inc"}],
+        "prices": {"AAPL": {"p": 172.4, "c": "USD"}},
+        "fx": {"USD": 1.0},
+        "base_currency": "USD",
+        "tone": "INTERMEDIATE",
+        "analysis": "NORMAL",
+        "lang": "it",
+    }
+    req = pa.parse_request(payload)
+    assert req.lang == "it"
+
+    async with factory() as session:
+        await pa.analyse(session, req)
+    system = next(m["content"] for m in captured["messages"] if m["role"] == "system")
+    assert "Respond in Italian" in system
+
+
+@pytest.mark.asyncio
+async def test_analyse_no_clause_when_lang_is_en(tmp_path, monkeypatch):
+    from app.services import portfolio_analysis as pa
+    from app.services.openrouter import LogResult
+
+    captured = {}
+
+    async def _fake_call_llm(client, messages, **kw):
+        captured["messages"] = messages
+        return LogResult(
+            content="Portfolio analysis in English.",
+            model="m", prompt_tokens=400, completion_tokens=100, cost_usd=0.0001,
+        )
+    monkeypatch.setattr(pa, "call_llm", _fake_call_llm)
+
+    _, factory, setup = _build_session_factory(tmp_path)
+    await setup()
+
+    payload = {
+        "positions": [{"yahoo_ticker": "AAPL", "qty": 10, "avg_cost": 150.0,
+                       "currency": "USD", "name": "Apple Inc"}],
+        "prices": {"AAPL": {"p": 172.4, "c": "USD"}},
+        "fx": {"USD": 1.0},
+        "base_currency": "USD",
+        "tone": "INTERMEDIATE",
+        "analysis": "NORMAL",
+        "lang": "en",
+    }
+    req = pa.parse_request(payload)
+    async with factory() as session:
+        await pa.analyse(session, req)
+    system = next(m["content"] for m in captured["messages"] if m["role"] == "system")
+    assert "Respond in" not in system