FA-61855 / Currency rounding and FX conversion / Member archive

A negative amount that rounds to zero prints as minus zero · case 05

A refund of -0.004 USD is rendered as '-0.00'.

Member previewVariant 5 · 3 implementations · 6 checks per implementation

Case contract

solve(amount, ccy): amount is an exact decimal string, ccy an ISO-like code that is trimmed and upper-cased. Minor-unit exponents: USD 2, EUR 2, JPY 0, KRW 0, KWD 3, BHD 3, CLF 4. Round the exact decimal half-even at the currency exponent and return a plain string with exactly that many fraction digits; a zero result is unsigned. Unknown codes return 'ERR:unknown-currency'.

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 signed-zero 1	`"-0.00"`	`"0.00"`	Failed

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