FA-68480 / Toll and parking fee computation / Member archive

Street meter time purchase: the accepted amount truncates partial minutes of charge · case 05

Street meter time purchase returns a wrong result when the accepted amount truncates partial minutes of charge.

Member previewVariant 5 · 3 implementations · 8 checks per implementation

Case contract

Input {now, expiry (or null), paid_cents, rate_per_hour, max_minutes, enf_start, enf_end, increment}. Only whole increments are credited. At or after enforcement end nothing is sold: [null, 0]. Paid time starts at the later of now, enforcement start and any unexpired expiry; it ends at the earliest of start + purchased minutes (floor), max(now, enf_start) + max_minutes, and enf_end. Accepted cents = min(credited, ceil(used minutes * rate/60)). Return [new expiry, accepted cents].

Why this case matters

Fee engines bill customers in integer cents; a wrong boundary, rounding stage or cap scope silently over- or under-charges.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
fee oracle 0	`[540, 83]`	`[540, 84]`	Failed

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