FA-60398 / Loyalty points ledgers / Member archive

Expiring point lots: availability pool · case 03

A redemption is accepted against expired points and then only partly filled.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

Events ["earn",day,pts,ttl] create a lot expiring at day+ttl (usable through that day); ["redeem",day,pts] draws only unexpired lots, soonest expiry first (ties by earn day), rejecting with "insufficient" when unexpired points are short; ["sweep",day] removes lots whose expiry is before day and reports the points removed. Emptied lots are dropped. Return {results, lots:[[expiry, earn_day, pts]]}.

Why this case matters

Member point balances, statements and the program liability depend on this ledger rule.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
expired unusable	`{"lots": [[30, 0, 200]], "results": [30, 95, [[95, 50]]]}`	`{"lots": [[30, 0, 200], [95, 5, 50]], "results": [30, 95, "insufficient"]}`	Failed

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