Add sort_params helper in CrudFactory (#103)

* feat: add sort_params helper in CrudFactory

* docs: add sorting

* fix: change sort_by to order_by

tests/test_exceptions.py

@@ -8,6 +8,7 @@ from fastapi_toolsets.exceptions import (
     ApiException,
     ConflictError,
     ForbiddenError,
+    InvalidOrderFieldError,
     NotFoundError,
     UnauthorizedError,
     generate_error_responses,
@@ -334,3 +335,43 @@ class TestExceptionIntegration:
 
         assert response.status_code == 200
         assert response.json() == {"id": 1}
+
+
+class TestInvalidOrderFieldError:
+    """Tests for InvalidOrderFieldError exception."""
+
+    def test_api_error_attributes(self):
+        """InvalidOrderFieldError has correct api_error metadata."""
+        assert InvalidOrderFieldError.api_error.code == 422
+        assert InvalidOrderFieldError.api_error.err_code == "SORT-422"
+        assert InvalidOrderFieldError.api_error.msg == "Invalid Order Field"
+
+    def test_stores_field_and_valid_fields(self):
+        """InvalidOrderFieldError stores field and valid_fields on the instance."""
+        error = InvalidOrderFieldError("unknown", ["name", "created_at"])
+        assert error.field == "unknown"
+        assert error.valid_fields == ["name", "created_at"]
+
+    def test_message_contains_field_and_valid_fields(self):
+        """Exception message mentions the bad field and valid options."""
+        error = InvalidOrderFieldError("bad_field", ["name", "email"])
+        assert "bad_field" in str(error)
+        assert "name" in str(error)
+        assert "email" in str(error)
+
+    def test_handled_as_422_by_exception_handler(self):
+        """init_exceptions_handlers turns InvalidOrderFieldError into a 422 response."""
+        app = FastAPI()
+        init_exceptions_handlers(app)
+
+        @app.get("/items")
+        async def list_items():
+            raise InvalidOrderFieldError("bad", ["name"])
+
+        client = TestClient(app)
+        response = client.get("/items")
+
+        assert response.status_code == 422
+        data = response.json()
+        assert data["error_code"] == "SORT-422"
+        assert data["status"] == "FAIL"