{"abstract":"Credit prorations of exactly half a minor unit round toward zero while debits round away.","category":"Subscription proration billing","checks":8,"contract":"Input {price (signed minor units), currency, num, den}. Exponents: USD 2, EUR 2, JPY 0, KWD 3, CLP 0. Amount = price*num/den rounded half away from zero. Display: zero-exponent currencies show an integer; others show sign, major units, a dot and exactly exponent digits, then a space and the code. Return {minor, display}.","contract_signature":"x","evaluation_group":"w2-subscription-proration-currency-minor-units","failed_approach":"The attempt floors the signed amount, over-crediting on any fractional credit.","family":"w2-subscription-proration-currency-minor-units-credit-rounding-direction","id":"FA-59516","implementations":{"attempt":{"sha256":"9946c2a2e7f20e7c412fbad5004a3efe391321e9fb7a5a0f4de616e9a328c1fa","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    exp = {'USD': 2, 'EUR': 2, 'JPY': 0, 'KWD': 3, 'CLP': 0}[x['currency']]\n    n = x['price'] * x['num']\n    v = n // x['den']\n    if exp == 0:\n        disp = str(v)\n    else:\n        sign = '-' if v < 0 else ''\n        q, r = divmod(abs(v), 10 ** exp)\n        disp = '%s%d.%0*d' % (sign, q, exp, r)\n    return {'minor': v, 'display': disp + ' ' + x['currency']}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression (boundary)', {'price': -3, 'currency': 'USD', 'num': 1, 'den': 2}, {'minor': -2, 'display': '-0.02 USD'}), ('regression (boundary)', {'price': -7, 'currency': 'KWD', 'num': 1, 'den': 2}, {'minor': -4, 'display': '-0.004 KWD'}), ('partial-repair probe (boundary)', {'price': 5, 'currency': 'JPY', 'num': 1, 'den': 2}, {'minor': 3, 'display': '3 JPY'}), ('partial-repair probe', {'price': 59, 'currency': 'JPY', 'num': 2, 'den': 4}, {'minor': 30, 'display': '30 JPY'}), ('normal control', {'price': -6310, 'currency': 'EUR', 'num': 23, 'den': 31}, {'minor': -4682, 'display': '-46.82 EUR'}), ('normal control', {'price': -35, 'currency': 'KWD', 'num': 30, 'den': 30}, {'minor': -35, 'display': '-0.035 KWD'}), ('normal control', {'price': 63, 'currency': 'JPY', 'num': 925, 'den': 1000}, {'minor': 58, 'display': '58 JPY'}), ('normal control', {'price': -18, 'currency': 'JPY', 'num': 81, 'den': 365}, {'minor': -4, 'display': '-4 JPY'})], [('regression (boundary)', {'price': -7, 'currency': 'KWD', 'num': 1, 'den': 2}, {'minor': -4, 'display': '-0.004 KWD'}), ('regression (boundary)', {'price': -105, 'currency': 'EUR', 'num': 1, 'den': 2}, {'minor': -53, 'display': '-0.53 EUR'}), ('partial-repair probe', {'price': 26, 'currency': 'KWD', 'num': 3, 'den': 31}, {'minor': 3, 'display': '0.003 KWD'}), ('partial-repair probe', {'price': -79, 'currency': 'JPY', 'num': 200, 'den': 365}, {'minor': -43, 'display': '-43 JPY'}), ('normal control', {'price': -48, 'currency': 'JPY', 'num': 0, 'den': 4}, {'minor': 0, 'display': '0 JPY'}), ('normal control', {'price': -88, 'currency': 'KWD', 'num': 15, 'den': 31}, {'minor': -43, 'display': '-0.043 KWD'}), ('normal control', {'price': -20, 'currency': 'USD', 'num': 1, 'den': 2}, {'minor': -10, 'display': '-0.10 USD'}), ('normal control', {'price': -93, 'currency': 'EUR', 'num': 0, 'den': 2}, {'minor': 0, 'display': '0.00 EUR'})], [('regression (boundary)', {'price': -105, 'currency': 'EUR', 'num': 1, 'den': 2}, {'minor': -53, 'display': '-0.53 EUR'}), ('regression', {'price': -51, 'currency': 'EUR', 'num': 1, 'den': 2}, {'minor': -26, 'display': '-0.26 EUR'}), ('partial-repair probe', {'price': -29, 'currency': 'USD', 'num': 316, 'den': 1000}, {'minor': -9, 'display': '-0.09 USD'}), ('partial-repair probe', {'price': 675691, 'currency': 'KWD', 'num': 214, 'den': 365}, {'minor': 396159, 'display': '396.159 KWD'}), ('normal control', {'price': 464209, 'currency': 'EUR', 'num': 10, 'den': 30}, {'minor': 154736, 'display': '1547.36 EUR'}), ('normal control', {'price': 61, 'currency': 'JPY', 'num': 50, 'den': 365}, {'minor': 8, 'display': '8 JPY'}), ('normal control', {'price': -28, 'currency': 'EUR', 'num': 30, 'den': 30}, {'minor': -28, 'display': '-0.28 EUR'}), ('normal control', {'price': 95, 'currency': 'USD', 'num': 25, 'den': 30}, {'minor': 79, 'display': '0.79 USD'})], [('regression', {'price': -51, 'currency': 'EUR', 'num': 1, 'den': 2}, {'minor': -26, 'display': '-0.26 EUR'}), ('regression', {'price': -98, 'currency': 'CLP', 'num': 3, 'den': 4}, {'minor': -74, 'display': '-74 CLP'}), ('partial-repair probe', {'price': -357324, 'currency': 'USD', 'num': 19, 'den': 30}, {'minor': -226305, 'display': '-2263.05 USD'}), ('partial-repair probe', {'price': 248141, 'currency': 'EUR', 'num': 187, 'den': 365}, {'minor': 127130, 'display': '1271.30 EUR'}), ('normal control', {'price': 553663, 'currency': 'USD', 'num': 138, 'den': 365}, {'minor': 209330, 'display': '2093.30 USD'}), ('normal control', {'price': 86, 'currency': 'EUR', 'num': 0, 'den': 2}, {'minor': 0, 'display': '0.00 EUR'}), ('normal control', {'price': 21, 'currency': 'JPY', 'num': 3, 'den': 30}, {'minor': 2, 'display': '2 JPY'}), ('normal control', {'price': 127, 'currency': 'JPY', 'num': 0, 'den': 2}, {'minor': 0, 'display': '0 JPY'})], [('regression', {'price': -98, 'currency': 'CLP', 'num': 3, 'den': 4}, {'minor': -74, 'display': '-74 CLP'}), ('regression', {'price': -25, 'currency': 'EUR', 'num': 1, 'den': 2}, {'minor': -13, 'display': '-0.13 EUR'}), ('partial-repair probe', {'price': -70, 'currency': 'JPY', 'num': 209, 'den': 365}, {'minor': -40, 'display': '-40 JPY'}), ('partial-repair probe', {'price': 26512, 'currency': 'USD', 'num': 248, 'den': 365}, {'minor': 18014, 'display': '180.14 USD'}), ('normal control', {'price': -74, 'currency': 'KWD', 'num': 111, 'den': 365}, {'minor': -23, 'display': '-0.023 KWD'}), ('normal control', {'price': 8, 'currency': 'EUR', 'num': 25, 'den': 31}, {'minor': 6, 'display': '0.06 EUR'}), ('normal control', {'price': -19, 'currency': 'EUR', 'num': 0, 'den': 31}, {'minor': 0, 'display': '0.00 EUR'}), ('normal control', {'price': 441137, 'currency': 'CLP', 'num': 2, 'den': 2}, {'minor': 441137, 'display': '441137 CLP'})]]\nfor i, (label, args, expected) in enumerate(fixtures[N-1]):\n    check(\"%s %d\" % (label, i), solve(args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"f82fccf2f37e6c9c46c543dd29ae1a01a03148b05f40436cd50e086a7a874939","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\n\nN = 1\nobservations = []\ndef solve(x):\n    exp = {'USD': 2, 'EUR': 2, 'JPY': 0, 'KWD': 3, 'CLP': 0}[x['currency']]\n    n = x['price'] * x['num']\n    v = (n * 2 + x['den']) // (2 * x['den'])\n    if exp == 0:\n        disp = str(v)\n    else:\n        sign = '-' if v < 0 else ''\n        q, r = divmod(abs(v), 10 ** exp)\n        disp = '%s%d.%0*d' % (sign, q, exp, r)\n    return {'minor': v, 'display': disp + ' ' + x['currency']}\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\nfixtures = [[('regression (boundary)', {'price': -3, 'currency': 'USD', 'num': 1, 'den': 2}, {'minor': -2, 'display': '-0.02 USD'}), ('regression (boundary)', {'price': -7, 'currency': 'KWD', 'num': 1, 'den': 2}, {'minor': -4, 'display': '-0.004 KWD'}), ('partial-repair probe (boundary)', {'price': 5, 'currency': 'JPY', 'num': 1, 'den': 2}, {'minor': 3, 'display': '3 JPY'}), ('partial-repair probe', {'price': 59, 'currency': 'JPY', 'num': 2, 'den': 4}, {'minor': 30, 'display': '30 JPY'}), ('normal control', {'price': -6310, 'currency': 'EUR', 'num': 23, 'den': 31}, {'minor': -4682, 'display': '-46.82 EUR'}), ('normal control', {'price': -35, 'currency': 'KWD', 'num': 30, 'den': 30}, {'minor': -35, 'display': '-0.035 KWD'}), ('normal control', {'price': 63, 'currency': 'JPY', 'num': 925, 'den': 1000}, {'minor': 58, 'display': '58 JPY'}), ('normal control', {'price': -18, 'currency': 'JPY', 'num': 81, 'den': 365}, {'minor': -4, 'display': '-4 JPY'})], [('regression (boundary)', {'price': -7, 'currency': 'KWD', 'num': 1, 'den': 2}, {'minor': -4, 'display': '-0.004 KWD'}), ('regression (boundary)', {'price': -105, 'currency': 'EUR', 'num': 1, 'den': 2}, {'minor': -53, 'display': '-0.53 EUR'}), ('partial-repair probe', {'price': 26, 'currency': 'KWD', 'num': 3, 'den': 31}, {'minor': 3, 'display': '0.003 KWD'}), ('partial-repair probe', {'price': -79, 'currency': 'JPY', 'num': 200, 'den': 365}, {'minor': -43, 'display': '-43 JPY'}), ('normal control', {'price': -48, 'currency': 'JPY', 'num': 0, 'den': 4}, {'minor': 0, 'display': '0 JPY'}), ('normal control', {'price': -88, 'currency': 'KWD', 'num': 15, 'den': 31}, {'minor': -43, 'display': '-0.043 KWD'}), ('normal control', {'price': -20, 'currency': 'USD', 'num': 1, 'den': 2}, {'minor': -10, 'display': '-0.10 USD'}), ('normal control', {'price': -93, 'currency': 'EUR', 'num': 0, 'den': 2}, {'minor': 0, 'display': '0.00 EUR'})], [('regression (boundary)', {'price': -105, 'currency': 'EUR', 'num': 1, 'den': 2}, {'minor': -53, 'display': '-0.53 EUR'}), ('regression', {'price': -51, 'currency': 'EUR', 'num': 1, 'den': 2}, {'minor': -26, 'display': '-0.26 EUR'}), ('partial-repair probe', {'price': -29, 'currency': 'USD', 'num': 316, 'den': 1000}, {'minor': -9, 'display': '-0.09 USD'}), ('partial-repair probe', {'price': 675691, 'currency': 'KWD', 'num': 214, 'den': 365}, {'minor': 396159, 'display': '396.159 KWD'}), ('normal control', {'price': 464209, 'currency': 'EUR', 'num': 10, 'den': 30}, {'minor': 154736, 'display': '1547.36 EUR'}), ('normal control', {'price': 61, 'currency': 'JPY', 'num': 50, 'den': 365}, {'minor': 8, 'display': '8 JPY'}), ('normal control', {'price': -28, 'currency': 'EUR', 'num': 30, 'den': 30}, {'minor': -28, 'display': '-0.28 EUR'}), ('normal control', {'price': 95, 'currency': 'USD', 'num': 25, 'den': 30}, {'minor': 79, 'display': '0.79 USD'})], [('regression', {'price': -51, 'currency': 'EUR', 'num': 1, 'den': 2}, {'minor': -26, 'display': '-0.26 EUR'}), ('regression', {'price': -98, 'currency': 'CLP', 'num': 3, 'den': 4}, {'minor': -74, 'display': '-74 CLP'}), ('partial-repair probe', {'price': -357324, 'currency': 'USD', 'num': 19, 'den': 30}, {'minor': -226305, 'display': '-2263.05 USD'}), ('partial-repair probe', {'price': 248141, 'currency': 'EUR', 'num': 187, 'den': 365}, {'minor': 127130, 'display': '1271.30 EUR'}), ('normal control', {'price': 553663, 'currency': 'USD', 'num': 138, 'den': 365}, {'minor': 209330, 'display': '2093.30 USD'}), ('normal control', {'price': 86, 'currency': 'EUR', 'num': 0, 'den': 2}, {'minor': 0, 'display': '0.00 EUR'}), ('normal control', {'price': 21, 'currency': 'JPY', 'num': 3, 'den': 30}, {'minor': 2, 'display': '2 JPY'}), ('normal control', {'price': 127, 'currency': 'JPY', 'num': 0, 'den': 2}, {'minor': 0, 'display': '0 JPY'})], [('regression', {'price': -98, 'currency': 'CLP', 'num': 3, 'den': 4}, {'minor': -74, 'display': '-74 CLP'}), ('regression', {'price': -25, 'currency': 'EUR', 'num': 1, 'den': 2}, {'minor': -13, 'display': '-0.13 EUR'}), ('partial-repair probe', {'price': -70, 'currency': 'JPY', 'num': 209, 'den': 365}, {'minor': -40, 'display': '-40 JPY'}), ('partial-repair probe', {'price': 26512, 'currency': 'USD', 'num': 248, 'den': 365}, {'minor': 18014, 'display': '180.14 USD'}), ('normal control', {'price': -74, 'currency': 'KWD', 'num': 111, 'den': 365}, {'minor': -23, 'display': '-0.023 KWD'}), ('normal control', {'price': 8, 'currency': 'EUR', 'num': 25, 'den': 31}, {'minor': 6, 'display': '0.06 EUR'}), ('normal control', {'price': -19, 'currency': 'EUR', 'num': 0, 'den': 31}, {'minor': 0, 'display': '0.00 EUR'}), ('normal control', {'price': 441137, 'currency': 'CLP', 'num': 2, 'den': 2}, {'minor': 441137, 'display': '441137 CLP'})]]\nfor i, (label, args, expected) in enumerate(fixtures[N-1]):\n    check(\"%s %d\" % (label, i), solve(args), expected)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"A deterministic teaching model of a stipulated billing rule. It makes no claim to reproduce any billing provider's exact behaviour and is not billing software. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"w2-subscription-proration-currency-minor-units-credit-rounding-direction","generated_at":"2026-09-29T14:46:37.047750+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"Prorated amounts must round and render in each currency's own minor-unit precision, including credits.","root_cause":"The signed amount is rounded half toward positive infinity instead of half away from zero.","sha256":"1e62e8f40951f1889575dd5764cd747fda705b8436b55153399b89a5883e11de","title":"Prorated amounts in currency minor units: credit rounding direction · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verified":true,"visibility":"public","verification":{"attempt":{"elapsed_ms":40.038,"exit_code":1,"observations":[{"actual":{"display":"-0.02 USD","minor":-2},"check":"regression (boundary) 0","expected":{"display":"-0.02 USD","minor":-2},"passed":true},{"actual":{"display":"-0.004 KWD","minor":-4},"check":"regression (boundary) 1","expected":{"display":"-0.004 KWD","minor":-4},"passed":true},{"actual":{"display":"2 JPY","minor":2},"check":"partial-repair probe (boundary) 2","expected":{"display":"3 JPY","minor":3},"passed":false},{"actual":{"display":"29 JPY","minor":29},"check":"partial-repair probe 3","expected":{"display":"30 JPY","minor":30},"passed":false},{"actual":{"display":"-46.82 EUR","minor":-4682},"check":"normal control 4","expected":{"display":"-46.82 EUR","minor":-4682},"passed":true},{"actual":{"display":"-0.035 KWD","minor":-35},"check":"normal control 5","expected":{"display":"-0.035 KWD","minor":-35},"passed":true},{"actual":{"display":"58 JPY","minor":58},"check":"normal control 6","expected":{"display":"58 JPY","minor":58},"passed":true},{"actual":{"display":"-4 JPY","minor":-4},"check":"normal control 7","expected":{"display":"-4 JPY","minor":-4},"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression (boundary) 0\", \"actual\": {\"minor\": -2, \"display\": \"-0.02 USD\"}, \"expected\": {\"minor\": -2, \"display\": \"-0.02 USD\"}, \"passed\": true}, {\"check\": \"regression (boundary) 1\", \"actual\": {\"minor\": -4, \"display\": \"-0.004 KWD\"}, \"expected\": {\"minor\": -4, \"display\": \"-0.004 KWD\"}, \"passed\": true}, {\"check\": \"partial-repair probe (boundary) 2\", \"actual\": {\"minor\": 2, \"display\": \"2 JPY\"}, \"expected\": {\"minor\": 3, \"display\": \"3 JPY\"}, \"passed\": false}, {\"check\": \"partial-repair probe 3\", \"actual\": {\"minor\": 29, \"display\": \"29 JPY\"}, \"expected\": {\"minor\": 30, \"display\": \"30 JPY\"}, \"passed\": false}, {\"check\": \"normal control 4\", \"actual\": {\"minor\": -4682, \"display\": \"-46.82 EUR\"}, \"expected\": {\"minor\": -4682, \"display\": \"-46.82 EUR\"}, \"passed\": true}, {\"check\": \"normal control 5\", \"actual\": {\"minor\": -35, \"display\": \"-0.035 KWD\"}, \"expected\": {\"minor\": -35, \"display\": \"-0.035 KWD\"}, \"passed\": true}, {\"check\": \"normal control 6\", \"actual\": {\"minor\": 58, \"display\": \"58 JPY\"}, \"expected\": {\"minor\": 58, \"display\": \"58 JPY\"}, \"passed\": true}, {\"check\": \"normal control 7\", \"actual\": {\"minor\": -4, \"display\": \"-4 JPY\"}, \"expected\": {\"minor\": -4, \"display\": \"-4 JPY\"}, \"passed\": true}], \"passed\": false}\n"},"broken":{"elapsed_ms":40.743,"exit_code":1,"observations":[{"actual":{"display":"-0.01 USD","minor":-1},"check":"regression (boundary) 0","expected":{"display":"-0.02 USD","minor":-2},"passed":false},{"actual":{"display":"-0.003 KWD","minor":-3},"check":"regression (boundary) 1","expected":{"display":"-0.004 KWD","minor":-4},"passed":false},{"actual":{"display":"3 JPY","minor":3},"check":"partial-repair probe (boundary) 2","expected":{"display":"3 JPY","minor":3},"passed":true},{"actual":{"display":"30 JPY","minor":30},"check":"partial-repair probe 3","expected":{"display":"30 JPY","minor":30},"passed":true},{"actual":{"display":"-46.82 EUR","minor":-4682},"check":"normal control 4","expected":{"display":"-46.82 EUR","minor":-4682},"passed":true},{"actual":{"display":"-0.035 KWD","minor":-35},"check":"normal control 5","expected":{"display":"-0.035 KWD","minor":-35},"passed":true},{"actual":{"display":"58 JPY","minor":58},"check":"normal control 6","expected":{"display":"58 JPY","minor":58},"passed":true},{"actual":{"display":"-4 JPY","minor":-4},"check":"normal control 7","expected":{"display":"-4 JPY","minor":-4},"passed":true}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"regression (boundary) 0\", \"actual\": {\"minor\": -1, \"display\": \"-0.01 USD\"}, \"expected\": {\"minor\": -2, \"display\": \"-0.02 USD\"}, \"passed\": false}, {\"check\": \"regression (boundary) 1\", \"actual\": {\"minor\": -3, \"display\": \"-0.003 KWD\"}, \"expected\": {\"minor\": -4, \"display\": \"-0.004 KWD\"}, \"passed\": false}, {\"check\": \"partial-repair probe (boundary) 2\", \"actual\": {\"minor\": 3, \"display\": \"3 JPY\"}, \"expected\": {\"minor\": 3, \"display\": \"3 JPY\"}, \"passed\": true}, {\"check\": \"partial-repair probe 3\", \"actual\": {\"minor\": 30, \"display\": \"30 JPY\"}, \"expected\": {\"minor\": 30, \"display\": \"30 JPY\"}, \"passed\": true}, {\"check\": \"normal control 4\", \"actual\": {\"minor\": -4682, \"display\": \"-46.82 EUR\"}, \"expected\": {\"minor\": -4682, \"display\": \"-46.82 EUR\"}, \"passed\": true}, {\"check\": \"normal control 5\", \"actual\": {\"minor\": -35, \"display\": \"-0.035 KWD\"}, \"expected\": {\"minor\": -35, \"display\": \"-0.035 KWD\"}, \"passed\": true}, {\"check\": \"normal control 6\", \"actual\": {\"minor\": 58, \"display\": \"58 JPY\"}, \"expected\": {\"minor\": 58, \"display\": \"58 JPY\"}, \"passed\": true}, {\"check\": \"normal control 7\", \"actual\": {\"minor\": -4, \"display\": \"-4 JPY\"}, \"expected\": {\"minor\": -4, \"display\": \"-4 JPY\"}, \"passed\": true}], \"passed\": false}\n"}},"member_only":{"stages":["fixed"],"fields":["implementations.fixed","verification.fixed","harness","repair"],"note":"The verified repair, its recorded checks, the repair description, and the scoring harness are available to members."}}