fix(db): 收斂 DatabaseManager PostgreSQL 連線池

tests/test_database_manager_cache.py

@@ -14,3 +14,48 @@ def test_database_manager_reuses_engine_for_same_sqlite_path(tmp_path):
     finally:
         DatabaseManager._instance_cache.clear()
         first.engine.dispose()
+
+
+def test_database_manager_uses_bounded_postgres_pool(monkeypatch):
+    import config
+    import database.manager as manager
+
+    captured = {}
+
+    class FakeEngine:
+        def dispose(self):
+            pass
+
+    class FakeSession:
+        pass
+
+    def fake_create_engine(url, **kwargs):
+        captured["url"] = url
+        captured["kwargs"] = kwargs
+        return FakeEngine()
+
+    def fake_sessionmaker(bind):
+        captured["session_bind"] = bind
+        return FakeSession
+
+    DatabaseManager._instance_cache.clear()
+    monkeypatch.setattr(config, "DATABASE_TYPE", "postgresql")
+    monkeypatch.setattr(config, "DATABASE_PATH", "postgresql://example/db")
+    monkeypatch.setattr(manager, "create_engine", fake_create_engine)
+    monkeypatch.setattr(manager, "sessionmaker", fake_sessionmaker)
+    monkeypatch.setattr(manager, "ensure_metadata_initialized", lambda *args, **kwargs: None)
+    monkeypatch.setattr(DatabaseManager, "_init_autoheal_tables", lambda self: None)
+
+    db = DatabaseManager()
+
+    assert captured["url"] == "postgresql://example/db"
+    assert captured["kwargs"]["pool_pre_ping"] is True
+    assert captured["kwargs"]["pool_size"] == 2
+    assert captured["kwargs"]["max_overflow"] == 3
+    assert captured["kwargs"]["pool_recycle"] == 1800
+    assert captured["kwargs"]["pool_timeout"] == 30
+    assert captured["kwargs"]["connect_args"]["connect_timeout"] == 10
+    assert "statement_timeout=60000" in captured["kwargs"]["connect_args"]["options"]
+    assert db.engine is captured["session_bind"]
+
+    DatabaseManager._instance_cache.clear()