feat: add advisory product comparison tool

tests/unit/service/test_advisor_base_adapter.py

@@ -24,6 +24,7 @@ def test_advisor_is_registered_through_the_new_base_factory() -> None:
         "analyze_portfolio",
         "generate_asset_allocation",
         "recommend_products",
+        "compare_products",
     )
     assert definition.supported_intents == (
         "fund_quote",

tests/unit/service/test_product_comparison_service.py

@@ -0,0 +1,43 @@
+import pytest
+from pydantic import ValidationError
+
+from app.core.product_comparison_contracts import ProductComparisonQuery
+from app.service.agent.implementations.advisor import AdvisorAgent
+from app.service.product_comparison_service import ProductComparisonService
+
+
+def test_comparison_query_requires_two_to_four_six_digit_codes() -> None:
+    assert ProductComparisonQuery(product_codes=["159511", "510500"]).product_codes == (
+        "159511", "510500"
+    )
+    with pytest.raises(ValidationError):
+        ProductComparisonQuery(product_codes=["159511"])
+    with pytest.raises(ValidationError):
+        ProductComparisonQuery(product_codes=["15951x", "510500"])
+
+
+def test_comparison_differences_only_contains_changed_fields() -> None:
+    rows = [
+        {"product_category": "ETF", "suitability_risk_level": "R2", "fund_type": "股票型",
+         "performance_benchmark": "沪深300", "management_fee_rate_pct": "0.50",
+         "custodian_fee_rate_pct": "0.10"},
+        {"product_category": "LOF", "suitability_risk_level": "R2", "fund_type": "股票型",
+         "performance_benchmark": "沪深300", "management_fee_rate_pct": "0.60",
+         "custodian_fee_rate_pct": "0.10"},
+    ]
+
+    result = ProductComparisonService._differences(rows)
+
+    assert set(result) == {"product_category", "management_fee_rate_pct"}
+
+
+def test_advisor_comparison_description_is_analysis_only() -> None:
+    text = AdvisorAgent._describe_comparison({
+        "status": "ready",
+        "products": [{"product_code": "159511", "product_name": "南方测试ETF"}],
+        "common_industries": ["科技"],
+    })
+
+    assert "159511 南方测试ETF" in text
+    assert "科技" in text
+    assert "不构成交易指令" in text