FA-62299 / Currency rounding and FX conversion / Member archive

A request below the smallest note is charged the fee · case 04

The customer pays the ATM fee for a withdrawal that dispensed nothing.

Member previewVariant 4 · 3 implementations · 6 checks per implementation

Case contract

solve(home_minor, rate, note, fee_minor): a request of home_minor home cents at rate foreign major units per home major unit is dispensed as the largest multiple of the smallest note not exceeding the converted amount (floor). If nothing can be dispensed return 'ERR:below-min-note'. The customer is charged the dispensed foreign amount converted back at the same rate, rounded UP to a home cent, plus fee_minor. Return [foreign_dispensed, charged_minor].

Why this case matters

Currency amounts must be rounded at the right stage and in the right unit, or ledgers, quotes and settlements drift by minor units.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression zero-dispense 1	`[0, 250]`	`"ERR:below-min-note"`	Failed

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