test-plan

Test Plan: Refund Eligibility

A filled-in example of the test plan this agent produces before writing code. Copy the shape for any new behavior: enumerate cases by type, mark scope, and state how to run + gate.

Behavior under test

`isRefundEligible(order, now)` decides whether an order can be refunded. An order is eligible when it was placed within the last 30 days, is unused, and has not already been refunded.

Cases

| # | Case | Type | Expected | |---|---|---|---| | 1 | order placed 5 days ago, unused | happy | `true` | | 2 | order placed exactly 30 days ago | boundary | `true` (inclusive) | | 3 | order placed 31 days ago | boundary | `false` | | 4 | order placed 0 days ago (today) | boundary | `true` | | 5 | order already marked refunded | failure | throws `AlreadyRefunded` | | 6 | order is `null` / missing | failure | throws `NotFound` | | 7 | order used (redeemed) | edge | `false` |

Determinism notes

• `now` is **injected**, not read from the system clock, so the 30-day boundary tests are

stable. The suite freezes `now` to `2026-06-29T12:00:00Z`.

• No network or DB access — `order` is built by a `makeOrder(overrides)` factory.

Out of scope (tracked separately)

• Partial refunds and refund *amount* calculation — separate behavior, separate plan.
• Payment-provider interaction — covered by an integration test, not this unit.

Coverage target

80% minimum (branch coverage emphasized — every `true`/`false`/throw path above is exercised).

How to run

# Run just this behavior's tests
npm test -- refund

# Gate coverage in CI (fails below 80%)
node scripts/check-coverage.mjs coverage/coverage-summary.json --min=80

Red → Green evidence (to be filled at implementation time)

RED:   5 failing — isRefundEligible is not defined
GREEN: 7 passing — statements 92% · branches 88% · target 80% met
Gaps:  none for this behavior; partial-refund path intentionally deferred