orders-contract

The shared order schema — the source of truth for the request/response shape exchanged between orders-service (backend) and orders-frontend (BFF/client).

• Wire format: all JSON keys are snake_case.
• parse_order_request(dict) -> OrderRequest validates an incoming request.
• parse_order_patch(dict) -> OrderPatch validates a partial (PATCH) update.
• compute_subtotal(OrderRequest) -> float is the reference subtotal calculation.

Both the service and the frontend must agree with this schema. When the schema changes, both consumers must be updated to match.

Shapes

Full-order response (OrderResponse)

{
  "order_id": "o1",
  "customer_id": "c1",
  "items": [
    {"sku": "a", "qty": 2, "unit_price": 50.0}
  ],
  "subtotal": 100.0,
  "total": 110.0
}

Serialize with order_response_to_dict(OrderResponse) -> dict (nested items are serialized to snake_case dicts).

Patch (OrderPatch)

A partial update — any subset of the mutable fields may be present. Omitted fields stay None.

{
  "customer_id": "c2",
  "items": [
    {"sku": "x", "qty": 3, "unit_price": 5.0}
  ]
}

When customer_id is present it must be a non-empty string; when items is present it must be a non-empty list of valid items. Invalid input raises ValueError.

python3 test_contract.py