test: CMA自动化测试补覆盖 226→452用例, 覆盖率36%→60%

- 新增8个测试文件(bot_bridge/kpi_causality/cash/predict/reports/tax_compliance/expenses/probe_cost)
- 增强 budget/auth/users + conftest账套模式适配
- 测试驱动修复: bot_bridge导入batch_id→source_batch; cash_forecast extra空dict
- 全量: 451 passed, 1 xfailed; 报告 docs/cma-test-coverage-report.md

backend/tests/conftest.py

@@ -35,6 +35,38 @@ TEST_ENGINE = create_engine(
 )
 TEST_SESSION_LOCAL = sessionmaker(autocommit=False, autoflush=False, bind=TEST_ENGINE)
 
+
+# MySQL-only 的 date_format() 在 SQLite 下注册等价实现（仅测试库）
+# 生产用 MySQL 原生函数；此处仅为让测试能跑通 expenses 月度累计校验/stats 统计
+def _sqlite_date_format(dt_val, fmt):
+    if dt_val is None:
+        return None
+    import datetime as _dt
+    if isinstance(dt_val, str):
+        for f in ("%Y-%m-%d %H:%M:%S", "%Y-%m-%d", "%Y-%m"):
+            try:
+                dt_val = _dt.datetime.strptime(str(dt_val)[:19], f)
+                break
+            except ValueError:
+                continue
+        else:
+            return None
+    if isinstance(dt_val, _dt.datetime):
+        d = dt_val
+    elif isinstance(dt_val, _dt.date):
+        d = _dt.datetime(dt_val.year, dt_val.month, dt_val.day)
+    else:
+        return None
+    return {
+        "%Y": f"{d.year:04d}",
+        "%Y-%m": f"{d.year:04d}-{d.month:02d}",
+        "%Y-%m-%d": f"{d.year:04d}-{d.month:02d}-{d.day:02d}",
+    }.get(fmt)
+
+
+from sqlalchemy import event  # noqa: E402
+event.listen(TEST_ENGINE, "connect", lambda dbapi_conn, rec: dbapi_conn.create_function("date_format", 2, _sqlite_date_format))
+
 # 替换 database 模块的全局引擎
 db_module._engine = TEST_ENGINE
 db_module._SessionLocal = TEST_SESSION_LOCAL
@@ -69,6 +101,13 @@ def db() -> Generator[Session, None, None]:
 def client(db) -> Generator[TestClient, None, None]:
     """提供测试 HTTP 客户端"""
     from app.main import app
+    from app.models import Entity
+
+    # 账套模式：确保测试库存在 entity_id=1 的active实体
+    ent = db.query(Entity).filter(Entity.id == 1).first()
+    if not ent:
+        db.add(Entity(id=1, name="测试企业", short_name="测试", status="active"))
+        db.commit()
 
     # 重写依赖，使用测试数据库
     app.dependency_overrides[db_module.get_db] = lambda: db
@@ -98,12 +137,16 @@ def create_test_user(db: Session, **kwargs) -> User:
 
 
 def get_token_for_user(client: TestClient, username: str = "testadmin", password: str = "admin123") -> str:
-    """获取测试用户的token"""
+    """获取测试用户的token（账套模式：需entity_id）"""
     resp = client.post("/api/cma/auth/login", json={
         "username": username,
         "password": password,
+        "entity_id": 1,
     })
-    return resp.json()["token"]
+    if resp.status_code != 200:
+        raise RuntimeError(f"登录失败: {resp.status_code} {resp.text[:300]}")
+    data = resp.json()
+    return data.get("token") or data.get("access_token")
 
 
 def auth_header(token: str) -> dict: