This is an intentionally broken, standard-library-only Python exercise. Copy cart.py and checks.py into a fresh directory outside the LoopX checkout. Use Python 3.11 or later. Run:
python3 checks.pyExpected starting result: six checks, two failures, exit status 1. The failures concern an empty cart and the free-shipping threshold. After the repair, the same six checks must pass with exit status 0.
The independent requirements are:
- Inputs are nonnegative integer prices in cents.
- An empty cart costs zero, including shipping.
- A subtotal of at least 10,000 cents ships free.
- A smaller, nonempty cart adds 500 cents for shipping.
- Negative prices raise
ValueError; the input list stays unchanged.
Do not delete or weaken checks to obtain a green result. The intentionally
failing file is named checks.py so ordinary repository test discovery does
not collect this exercise as a failing product test.
The walkthrough shows how to give this task to LoopX, confirm host activation, inspect the patch, and make a local signed-off commit. It also includes a separate recurring bug-hunt prompt and the real-project PR workflow. No remote repository, network service, paid API, or model call is needed to run the six checks. An agent-driven repair uses the agent host's own account and usage.
This fixture demonstrates a repair exercise. Passing its checks does not qualify unattended host continuation, real-project bug discovery, or a learning benefit.