test: enforce provider construction ownership

tests/test_data_gateway.py

@@ -1,7 +1,9 @@
 from __future__ import annotations
 
+import ast
 import unittest
 from datetime import datetime, timedelta
+from pathlib import Path
 
 from backend.data import (
     DataPolicyError,
@@ -45,8 +47,6 @@ class DataGatewayTests(unittest.TestCase):
         self.assertIs(gateway.chart_data.ifind, gateway.ifind)
 
     def test_server_has_no_direct_runtime_tushare_construction(self) -> None:
-        from pathlib import Path
-
         source = (
             Path(__file__).resolve().parents[1]
             / "backend"
@@ -57,6 +57,33 @@ class DataGatewayTests(unittest.TestCase):
         self.assertEqual(source.count("TushareClient(self.token)"), 1)
         self.assertIn("return gateway.tushare()", source)
 
+    def test_provider_construction_has_unique_declared_owners(self) -> None:
+        root = Path(__file__).resolve().parents[1]
+        owners = {
+            "EastmoneyChartClient": {"backend/data/gateway.py"},
+            "IfindHttpClient": {"backend/data/gateway.py"},
+            "IfindProvider": {"backend/data/gateway.py"},
+            "MarketChartClient": {"backend/data/gateway.py"},
+            "TushareClient": {"backend/features/market/service.py"},
+            "TushareProvider": {"backend/data/gateway.py"},
+            "WebRealtimeAggregator": {"backend/data/gateway.py"},
+        }
+        found = {name: set() for name in owners}
+        for path in (root / "backend").rglob("*.py"):
+            relative = path.relative_to(root).as_posix()
+            tree = ast.parse(path.read_text(encoding="utf-8"), filename=str(path))
+            for node in ast.walk(tree):
+                if not isinstance(node, ast.Call):
+                    continue
+                name = getattr(node.func, "id", None) or getattr(node.func, "attr", None)
+                if name in found:
+                    found[name].add(relative)
+        self.assertEqual(found, owners)
+        provider_source = (root / "backend/data/providers/tushare.py").read_text(
+            encoding="utf-8"
+        )
+        self.assertIn("client_factory: Callable[[str], TushareClient] = TushareClient", provider_source)
+
     def test_quality_gate_accepts_matching_daily_evidence(self) -> None:
         timezone = market_timezone()
         now = datetime(2026, 7, 29, 16, 0, tzinfo=timezone)