Incident Dossier

The Invoice That Forgot Quantity

Black Friday. Support hears 'I ordered three and paid for one.' Stripe shows the wrong amount. The invoice printer multiplies unit price into cents — and never multiplies by quantity.

Initial failing signalqty 3 of $19.99 underchargesExpected behavior: The total for quantity 3 at $19.99 is 5997 cents. · actual behavior: The total is 1999 cents, charging for one item instead.

Progress

1Reproduce the bugRun checks

2Edit the fixOpen

3Pass checksOpen

4Submit fixOpen

Reproduction Steps

Sum line items with fractional dollar prices.
Compare totalCents to the true cent total.
Watch float residue get truncated away.

Focus Mode

Start

src/checkout.js
src/invoice.js

Likely area

src/invoice.js
src/checkout.js
src/cart.js

Challenge Coach

Hints reveal broad direction first, then narrow toward the suspect path without showing hidden tests or exact solution code.

TopicData Integrity

DifficultyMedium

Est. time15 min

Workspacepreparing

Explorer

Loading files

Evidence Map

Failing signal loaded from challenge API
Workspace files loaded from workspace API
Results rendered only after API run/submit

Autosaved

workspace

Outputread-onlyready$ prepare workspace

Preparing workspace