FA-62007 / Currency rounding and FX conversion / Member archive

Cash rounding is applied to each line instead of the basket total · case 02

A basket of 1.02 and 1.02 is charged 2.00 instead of 2.05.

Member previewVariant 2 · 3 implementations · 7 checks per implementation

Case contract

solve(lines, tender): lines are CHF decimal strings with up to three decimals (weight- or volume-priced items; refund lines negative). The exact total is their sum. For tender 'cash' (compared after trimming and lower-casing) the total is rounded to the nearest 0.05 with ties away from zero; every other tender ('card', 'twint', 'voucher', ...) pays the total rounded half-up to 0.01. Return [payable as a 2-decimal string, adjustment as a 3-decimal string] where adjustment = payable - exact; zeros are unsigned.

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 rounding-scope 1	`["-2.05", "-0.030"]`	`["-2.00", "0.020"]`	Failed

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