refactor: establish feature application service layout

tests/test_feature_boundaries.py

@@ -0,0 +1,56 @@
+from __future__ import annotations
+
+import ast
+import unittest
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[1]
+FEATURES = ROOT / "backend" / "features"
+
+
+class FeatureBoundaryTests(unittest.TestCase):
+    def test_feature_services_do_not_import_http_or_provider_adapters(self) -> None:
+        forbidden = {
+            "server",
+            "tushare_client",
+            "ifind_client",
+            "chart_data_provider",
+            "realtime_aggregator",
+        }
+        violations = []
+        for path in FEATURES.rglob("*.py"):
+            tree = ast.parse(path.read_text(encoding="utf-8"), filename=str(path))
+            for node in ast.walk(tree):
+                names = []
+                if isinstance(node, ast.Import):
+                    names = [alias.name for alias in node.names]
+                elif isinstance(node, ast.ImportFrom) and node.module:
+                    names = [node.module]
+                for name in names:
+                    if name.split(".")[0] in forbidden:
+                        violations.append(f"{path.relative_to(ROOT)} -> {name}")
+        self.assertEqual(violations, [])
+
+    def test_legacy_service_modules_are_compatibility_exports_only(self) -> None:
+        for filename in ("alert_service.py", "trade_journal.py", "strategy_tracking.py"):
+            tree = ast.parse((ROOT / filename).read_text(encoding="utf-8"))
+            definitions = [
+                node for node in tree.body
+                if isinstance(node, (ast.ClassDef, ast.FunctionDef, ast.AsyncFunctionDef))
+            ]
+            self.assertEqual(definitions, [], filename)
+
+    def test_each_migrated_feature_owns_one_application_service(self) -> None:
+        expected = {
+            "alerts/service.py": "AlertService",
+            "review/trade_journal.py": "TradeJournalService",
+            "screener/tracking.py": "StrategyTrackingService",
+        }
+        for relative, class_name in expected.items():
+            tree = ast.parse((FEATURES / relative).read_text(encoding="utf-8"))
+            self.assertIn(class_name, {node.name for node in tree.body if isinstance(node, ast.ClassDef)})
+
+
+if __name__ == "__main__":
+    unittest.main()