Order pages

medium 60 min Python Stripe Bug Squash-styleMeta AI-enabled coding-style

1 Page 2 shows an order twice
2 Build a feature
3 Make it fast

repo

shop/
tests/
visible/

read-only

# shop

A tiny order backend: orders, an order store, paged listing for the account page,
pricing, and a monthly report.

    shop/models.py      Order and Line
    shop/store.py       OrderStore: add orders, list them newest first
    shop/pagination.py  paginate(): one page of a list, plus has_next
    shop/api.py         list_orders(): what the account page calls
    shop/pricing.py     line and order totals, in cents
    shop/reports.py     monthly reports

Run the tests with `python -m pytest` (or press Run in the browser).

Phase 1 of 3 0:00

Page 2 shows an order twice

Support ticket #4821 · priority: high · from: support

Customers say that on their Orders page, page 2 starts with the same order that ended page 1. One customer thought she'd been charged twice. Please fix before the weekend sale.

The account page calls list_orders() in shop/api.py.

tests/visible/test_orders_page.py reproduces the report. Make it pass.
On Submit, hidden tests check paging much harder: every order shows up exactly once across all pages, page sizes are right, has_next is honest, and odd sizes work.

Bring your own AI: paste the copied repo into Claude, ChatGPT or Gemini. In a real interview the assistant usually reads the files itself. Or download the zip, work in your own editor, and upload the files you changed.