FA-62248 / Currency rounding and FX conversion / Member archive

Redenominated amounts are truncated · case 03

Old balances lose up to one new minor unit, and debts shrink toward zero.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

solve(amount_minor, date, cutover, factor, old_exp, new_exp): amounts dated on or after the cutover (ISO date strings) are already in the new currency and returned unchanged as [amount_minor, 'native']. Earlier amounts are old-currency minor units: new = amount_minor / factor * 10**(new_exp - old_exp), rounded half away from zero, returned as [new, 'converted']. factor is old units per new unit.

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 redenomination-rounding 1	`[1598014, "converted"]`	`[1598015, "converted"]`	Failed

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