README.md

The floor

Do not change anything in this directory, in fixtures/, or in .github/workflows/.

What it asserts

floor.test.ts and tool.floor.test.ts are a contract gate, not a correctness check. Between them they assert that:

• your service answers every example order in the agreed shape — a discountTotal, a list of discounts, each with an amount and a reason — and that bad input gets a 4xx rather than a crash;
• your tool declares at least one argument, and answers every call it is given rather than throwing an exception the caller has no way to catch.

They deliberately assert nothing about the discounts you calculate. The rules are open to interpretation in places, and how you read them is your decision to make and yours to explain. Nor do they check the format of what you return — only that the keys are there. How you represent money is yours to choose and yours to justify.

Clearing this gate is not a good score; it is the price of entry.

One check fails on a fresh clone: declares at least one argument. A tool with no arguments cannot be told which order to price, so that one is a task rather than a break. Everything else is green before you have written a line, which is how you know your toolchain works.

What it shows you

npm run report prints what your service returns for each example order, and then invokes your tool the way a model does — badly: nothing at all, arguments as a JSON string, a hallucinated product id, values of the wrong primitive type, a customer that does not exist, an argument you never declared.

It asserts nothing and cannot fail. It is worth reading anyway: it is the only view you get of what a caller sees when it gets something wrong, and whether that caller could tell what to do differently. The calls use the argument names your schema declares, because a real caller has your schema in front of it.

It also runs in CI, so the result is visible on the workflow run summary.

Submitting

Your submission includes the output of:

npm run verify:integrity

It compares the three protected paths against this repo's first commit — the one we handed over — so it keeps working however you obtained the repo and whatever you commit on top of it. If it prints a diff, you changed the floor, and we will read the submission as not having passed it.

It runs in CI too, as its own step, so a slip shows up on the run summary when you push rather than at review time.