add tests exclusion E402 rule (#73)

Author: wu-clan

.ruff.toml

@@ -42,3 +42,4 @@ order-by-type = true
 "backend/app/api/v1/*.py" = ["TCH"]
 "backend/app/models/*.py" = ["TCH003"]
 "backend/app/**/__init__.py" = ["F401"]
+"backend/app/tests/*.py" = ["E402"]

backend/app/models/__init__.py

@@ -4,7 +4,7 @@
 # 导入所有模型，并将 Base 放在最前面， 以便 Base 拥有它们
 # imported by Alembic
 """
-from backend.app.database.base_class import MappedBase  # F401
+from backend.app.database.base_class import MappedBase
 from backend.app.models.sys_api import Api
 from backend.app.models.sys_casbin_rule import CasbinRule
 from backend.app.models.sys_dept import Dept