FAILURE MAP
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FA-58286 / Double-entry ledger accounting / Open access

Payroll journal entry: year-to-date accumulation · case 01

A bonus paycheck in the same run is taxed as if the base had not been used.

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ROOT CAUSE

Year-to-date wages are not updated between paychecks in one run.

THE FAILURE

Year-to-date wages are not updated between paychecks in one run.

Unsuccessful approach: Accumulating gross minus the benefit understates wages that count toward the base.

Case contract

x = {'gross': [[employee, cents]] (an employee may appear twice), 'ytd': prior year-to-date gross, 'wage_base', 'ss_bp', 'med_bp', 'itax_bp', 'benefit': {employee: pre-tax deduction per paycheck}}. Per paycheck: social wages = min(gross, max(0, wage_base - ytd)), ytd then increases by gross; social tax = round(social wages * ss_bp / 10000), medicare = round(gross * med_bp / 10000) (no cap), income tax = round((gross - benefit) * itax_bp / 10000), all half-up; net = gross - social - medicare - income tax - benefit. The employer matches social and medicare. Return {'wage_expense', 'tax_expense', 'cash', 'withholding', 'benefits'} where withholding holds employee and employer taxes.

Why this case matters

Ledger software must keep debits equal to credits and apply normal-balance, period and cutoff rules exactly; small sign or boundary slips silently misstate financial statements.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    def rnd(n, d):
        q, r = divmod(n, d)
        return q + (1 if 2 * r >= d else 0)
    ytd = dict(x['ytd'])
    wage = tax_exp = cash = withholding = benefits = 0
    for emp, g in x['gross']:
        ben = x['benefit'].get(emp, 0)
        social = min(g, max(0, x['wage_base'] - ytd.get(emp, 0)))
        ss = rnd(social * x['ss_bp'], 10000)
        med = rnd(g * x['med_bp'], 10000)
        itax = rnd((g - ben) * x['itax_bp'], 10000)
        employer = ss + med
        wage += g
        tax_exp += employer
        cash += g - ss - med - itax - ben
        withholding += ss + med + itax + employer
        benefits += ben
    return {'wage_expense': wage, 'tax_expense': tax_exp, 'cash': cash, 'withholding': withholding, 'benefits': benefits}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['regression: year-to-date accumulation', {'gross': [['ann', 250000], ['cy', 333333], ['ann', 200000]], 'ytd': {'ann': 16700000, 'cy': 16700000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'ann': 12345, 'cy': 0}}, {'wage_expense': 783333, 'tax_expense': 31198, 'cash': 560544, 'withholding': 229297, 'benefits': 24690}], ['regression: year-to-date accumulation, partial-repair probe', {'gross': [['ann', 50000], ['di', 100000], ['ann', 80000]], 'ytd': {'ann': 16800000, 'di': 15000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'ann': 5000, 'di': 12345}}, {'wage_expense': 230000, 'tax_expense': 13255, 'cash': 148716, 'withholding': 72194, 'benefits': 22345}], ['control 1', {'gross': [['di', 1234], ['cy', 50000], ['bob', 50000], ['di', 80000]], 'ytd': {'di': 15000000, 'cy': 16800000, 'bob': 16800000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'di': 12345, 'cy': 0, 'bob': 5000}}, {'wage_expense': 181234, 'tax_expense': 13865, 'cash': 104339, 'withholding': 61070, 'benefits': 29690}], ['control 2', {'gross': [['bob', 100000]], 'ytd': {'bob': 16800000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'bob': 5000}}, {'wage_expense': 100000, 'tax_expense': 5170, 'cash': 78430, 'withholding': 21740, 'benefits': 5000}], ['control 3', {'gross': [['bob', 100000], ['ann', 250000], ['bob', 80000]], 'ytd': {'bob': 0, 'ann': 15000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'bob': 5000, 'ann': 0}}, {'wage_expense': 430000, 'tax_expense': 32895, 'cash': 294705, 'withholding': 158190, 'benefits': 10000}], ['control 4', {'gross': [['di', 50000], ['ann', 50000], ['cy', 1234]], 'ytd': {'di': 16800000, 'ann': 16800000, 'cy': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'di': 12345, 'ann': 0, 'cy': 5000}}, {'wage_expense': 101234, 'tax_expense': 7745, 'cash': 67755, 'withholding': 23879, 'benefits': 17345}], ['control 5', {'gross': [['ann', 333333], ['di', 100000], ['bob', 1234]], 'ytd': {'ann': 0, 'di': 17000000, 'bob': 16800000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'ann': 12345, 'di': 5000, 'bob': 5000}}, {'wage_expense': 434567, 'tax_expense': 27045, 'cash': 343955, 'withholding': 95312, 'benefits': 22345}]], [['regression: year-to-date accumulation', {'gross': [['bob', 100000], ['ann', 50000], ['bob', 80000]], 'ytd': {'bob': 16800000, 'ann': 17000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'bob': 5000, 'ann': 0}}, {'wage_expense': 230000, 'tax_expense': 7055, 'cash': 186545, 'withholding': 40510, 'benefits': 10000}], ['regression: year-to-date accumulation, partial-repair probe', {'gross': [['cy', 1234], ['bob', 100000], ['di', 250000], ['cy', 200000]], 'ytd': {'cy': 16800000, 'bob': 15000000, 'di': 15000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'cy': 12345, 'bob': 12345, 'di': 12345}}, {'wage_expense': 551234, 'tax_expense': 33413, 'cash': 408217, 'withholding': 127050, 'benefits': 49380}], ['control 1', {'gross': [['ann', 1234], ['bob', 100000], ['di', 50000], ['ann', 80000]], 'ytd': {'ann': 15000000, 'bob': 0, 'di': 17000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'ann': 0, 'bob': 12345, 'di': 12345}}, {'wage_expense': 231234, 'tax_expense': 14590, 'cash': 146515, 'withholding': 74619, 'benefits': 24690}], ['control 2', {'gross': [['cy', 50000], ['ann', 50000], ['di', 333333]], 'ytd': {'cy': 16700000, 'ann': 15000000, 'di': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'cy': 0, 'ann': 12345, 'di': 12345}}, {'wage_expense': 433333, 'tax_expense': 33150, 'cash': 334628, 'withholding': 107165, 'benefits': 24690}], ['control 3', {'gross': [['bob', 100000], ['ann', 250000]], 'ytd': {'bob': 15000000, 'ann': 15000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'bob': 12345, 'ann': 5000}}, {'wage_expense': 350000, 'tax_expense': 26775, 'cash': 272614, 'withholding': 86816, 'benefits': 17345}], ['control 4', {'gross': [['di', 100000], ['cy', 50000]], 'ytd': {'di': 16800000, 'cy': 16800000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'di': 12345, 'cy': 5000}}, {'wage_expense': 150000, 'tax_expense': 8995, 'cash': 94476, 'withholding': 47174, 'benefits': 17345}], ['control 5', {'gross': [['ann', 1234], ['bob', 1234], ['cy', 1234], ['ann', 80000]], 'ytd': {'ann': 0, 'bob': 16800000, 'cy': 17000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'ann': 12345, 'bob': 0, 'cy': 5000}}, {'wage_expense': 83702, 'tax_expense': 6328, 'cash': 41202, 'withholding': 19138, 'benefits': 29690}]], [['regression: year-to-date accumulation', {'gross': [['di', 250000], ['ann', 250000], ['di', 200000]], 'ytd': {'di': 16800000, 'ann': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'di': 12345, 'ann': 5000}}, {'wage_expense': 700000, 'tax_expense': 29370, 'cash': 560502, 'withholding': 139178, 'benefits': 29690}], ['regression: year-to-date accumulation, partial-repair probe', {'gross': [['cy', 50000], ['bob', 50000], ['cy', 200000]], 'ytd': {'cy': 16800000, 'bob': 16700000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'cy': 12345, 'bob': 12345}}, {'wage_expense': 300000, 'tax_expense': 11170, 'cash': 193943, 'withholding': 80192, 'benefits': 37035}], ['control 1', {'gross': [['ann', 250000], ['di', 333333], ['ann', 200000]], 'ytd': {'ann': 17000000, 'di': 15000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'ann': 5000, 'di': 12345}}, {'wage_expense': 783333, 'tax_expense': 32025, 'cash': 652864, 'withholding': 140149, 'benefits': 22345}], ['control 2', {'gross': [['ann', 50000], ['cy', 50000], ['bob', 100000]], 'ytd': {'ann': 0, 'cy': 0, 'bob': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'ann': 5000, 'cy': 5000, 'bob': 5000}}, {'wage_expense': 200000, 'tax_expense': 15300, 'cash': 147500, 'withholding': 52800, 'benefits': 15000}], ['control 3', {'gross': [['ann', 333333]], 'ytd': {'ann': 17000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'ann': 12345}}, {'wage_expense': 333333, 'tax_expense': 4833, 'cash': 284056, 'withholding': 41765, 'benefits': 12345}], ['control 4', {'gross': [['di', 50000], ['cy', 50000]], 'ytd': {'di': 16800000, 'cy': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'di': 5000, 'cy': 5000}}, {'wage_expense': 100000, 'tax_expense': 7650, 'cash': 71550, 'withholding': 26100, 'benefits': 10000}], ['control 5', {'gross': [['di', 250000], ['bob', 100000], ['cy', 1234], ['di', 200000]], 'ytd': {'di': 17000000, 'bob': 15000000, 'cy': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'di': 0, 'bob': 12345, 'cy': 5000}}, {'wage_expense': 551234, 'tax_expense': 14270, 'cash': 402164, 'withholding': 145995, 'benefits': 17345}]], [['regression: year-to-date accumulation', {'gross': [['bob', 1234], ['cy', 100000], ['ann', 100000], ['bob', 80000]], 'ytd': {'bob': 16800000, 'cy': 0, 'ann': 17000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'bob': 0, 'cy': 12345, 'ann': 5000}}, {'wage_expense': 281234, 'tax_expense': 13998, 'cash': 218224, 'withholding': 59663, 'benefits': 17345}], ['regression: year-to-date accumulation, partial-repair probe', {'gross': [['di', 100000], ['bob', 333333], ['ann', 250000], ['di', 200000]], 'ytd': {'di': 16700000, 'bob': 16700000, 'ann': 15000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'di': 5000, 'bob': 0, 'ann': 12345}}, {'wage_expense': 883333, 'tax_expense': 48148, 'cash': 709521, 'withholding': 199615, 'benefits': 22345}], ['control 1', {'gross': [['bob', 100000]], 'ytd': {'bob': 15000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'bob': 5000}}, {'wage_expense': 100000, 'tax_expense': 7650, 'cash': 77850, 'withholding': 24800, 'benefits': 5000}], ['control 2', {'gross': [['ann', 100000], ['bob', 100000], ['cy', 250000]], 'ytd': {'ann': 16700000, 'bob': 17000000, 'cy': 16700000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'ann': 12345, 'bob': 5000, 'cy': 0}}, {'wage_expense': 450000, 'tax_expense': 22645, 'cash': 314826, 'withholding': 140474, 'benefits': 17345}], ['control 3', {'gross': [['cy', 100000]], 'ytd': {'cy': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'cy': 5000}}, {'wage_expense': 100000, 'tax_expense': 7650, 'cash': 77850, 'withholding': 24800, 'benefits': 5000}], ['control 4', {'gross': [['di', 100000], ['bob', 333333]], 'ytd': {'di': 0, 'bob': 16700000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'di': 0, 'bob': 12345}}, {'wage_expense': 433333, 'tax_expense': 22403, 'cash': 356486, 'withholding': 86905, 'benefits': 12345}], ['control 5', {'gross': [['bob', 333333], ['di', 250000], ['ann', 50000], ['bob', 80000]], 'ytd': {'bob': 0, 'di': 16700000, 'ann': 16700000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'bob': 12345, 'di': 0, 'ann': 5000}}, {'wage_expense': 713333, 'tax_expense': 48990, 'cash': 566288, 'withholding': 166345, 'benefits': 29690}]], [['regression: year-to-date accumulation', {'gross': [['bob', 50000], ['bob', 200000]], 'ytd': {'bob': 16800000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'bob': 5000}}, {'wage_expense': 250000, 'tax_expense': 7345, 'cash': 208655, 'withholding': 38690, 'benefits': 10000}], ['control 1', {'gross': [['ann', 333333], ['bob', 250000], ['cy', 1234]], 'ytd': {'ann': 0, 'bob': 16700000, 'cy': 16800000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'ann': 5000, 'bob': 12345, 'cy': 0}}, {'wage_expense': 584567, 'tax_expense': 39140, 'cash': 403294, 'withholding': 203068, 'benefits': 17345}], ['control 2', {'gross': [['di', 1234], ['bob', 333333], ['di', 80000]], 'ytd': {'di': 15000000, 'bob': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'di': 0, 'bob': 0}}, {'wage_expense': 414567, 'tax_expense': 31715, 'cash': 291648, 'withholding': 154634, 'benefits': 0}], ['control 3', {'gross': [['di', 250000], ['di', 80000]], 'ytd': {'di': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'di': 5000}}, {'wage_expense': 330000, 'tax_expense': 25245, 'cash': 256355, 'withholding': 88890, 'benefits': 10000}], ['control 4', {'gross': [['di', 333333], ['bob', 100000], ['ann', 250000], ['di', 200000]], 'ytd': {'di': 17000000, 'bob': 17000000, 'ann': 16700000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'di': 5000, 'bob': 12345, 'ann': 12345}}, {'wage_expense': 883333, 'tax_expense': 22728, 'cash': 741050, 'withholding': 130321, 'benefits': 34690}], ['control 5', {'gross': [['bob', 100000], ['cy', 50000], ['ann', 100000]], 'ytd': {'bob': 15000000, 'cy': 16700000, 'ann': 16800000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'bob': 0, 'cy': 5000, 'ann': 12345}}, {'wage_expense': 250000, 'tax_expense': 16645, 'cash': 192744, 'withholding': 56556, 'benefits': 17345}], ['control 6', {'gross': [['di', 1234]], 'ytd': {'di': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'di': 5000}}, {'wage_expense': 1234, 'tax_expense': 95, 'cash': -3409, 'withholding': -262, 'benefits': 5000}]]]
for label, args, expected in fixtures[N-1]:
    try:
        actual = solve(args)
    except Exception as exc:
        actual = 'raised ' + type(exc).__name__
    check(label, actual, expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
regression: year-to-date accumulation{'benefits': 24690, 'cash': 550624, 'tax_expense': 41118, 'wage_expense': 783333, 'withholding': 249137}{'benefits': 24690, 'cash': 560544, 'tax_expense': 31198, 'wage_expense': 783333, 'withholding': 229297}Failed
regression: year-to-date accumulation, partial-repair probe{'benefits': 22345, 'cash': 145616, 'tax_expense': 16355, 'wage_expense': 230000, 'withholding': 78394}{'benefits': 22345, 'cash': 148716, 'tax_expense': 13255, 'wage_expense': 230000, 'withholding': 72194}Failed
control 1{'benefits': 29690, 'cash': 104339, 'tax_expense': 13865, 'wage_expense': 181234, 'withholding': 61070}{'benefits': 29690, 'cash': 104339, 'tax_expense': 13865, 'wage_expense': 181234, 'withholding': 61070}Passed
control 2{'benefits': 5000, 'cash': 78430, 'tax_expense': 5170, 'wage_expense': 100000, 'withholding': 21740}{'benefits': 5000, 'cash': 78430, 'tax_expense': 5170, 'wage_expense': 100000, 'withholding': 21740}Passed
control 3{'benefits': 10000, 'cash': 294705, 'tax_expense': 32895, 'wage_expense': 430000, 'withholding': 158190}{'benefits': 10000, 'cash': 294705, 'tax_expense': 32895, 'wage_expense': 430000, 'withholding': 158190}Passed
control 4{'benefits': 17345, 'cash': 67755, 'tax_expense': 7745, 'wage_expense': 101234, 'withholding': 23879}{'benefits': 17345, 'cash': 67755, 'tax_expense': 7745, 'wage_expense': 101234, 'withholding': 23879}Passed
control 5{'benefits': 22345, 'cash': 343955, 'tax_expense': 27045, 'wage_expense': 434567, 'withholding': 95312}{'benefits': 22345, 'cash': 343955, 'tax_expense': 27045, 'wage_expense': 434567, 'withholding': 95312}Passed

SHA-256 / 9c674497ae664f5ade0e6c549a425c804e318115050a97b29587cf755047ba99

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    def rnd(n, d):
        q, r = divmod(n, d)
        return q + (1 if 2 * r >= d else 0)
    ytd = dict(x['ytd'])
    wage = tax_exp = cash = withholding = benefits = 0
    for emp, g in x['gross']:
        ben = x['benefit'].get(emp, 0)
        social = min(g, max(0, x['wage_base'] - ytd.get(emp, 0)))
        ytd[emp] = ytd.get(emp, 0) + g - ben
        ss = rnd(social * x['ss_bp'], 10000)
        med = rnd(g * x['med_bp'], 10000)
        itax = rnd((g - ben) * x['itax_bp'], 10000)
        employer = ss + med
        wage += g
        tax_exp += employer
        cash += g - ss - med - itax - ben
        withholding += ss + med + itax + employer
        benefits += ben
    return {'wage_expense': wage, 'tax_expense': tax_exp, 'cash': cash, 'withholding': withholding, 'benefits': benefits}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['regression: year-to-date accumulation', {'gross': [['ann', 250000], ['cy', 333333], ['ann', 200000]], 'ytd': {'ann': 16700000, 'cy': 16700000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'ann': 12345, 'cy': 0}}, {'wage_expense': 783333, 'tax_expense': 31198, 'cash': 560544, 'withholding': 229297, 'benefits': 24690}], ['regression: year-to-date accumulation, partial-repair probe', {'gross': [['ann', 50000], ['di', 100000], ['ann', 80000]], 'ytd': {'ann': 16800000, 'di': 15000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'ann': 5000, 'di': 12345}}, {'wage_expense': 230000, 'tax_expense': 13255, 'cash': 148716, 'withholding': 72194, 'benefits': 22345}], ['control 1', {'gross': [['di', 1234], ['cy', 50000], ['bob', 50000], ['di', 80000]], 'ytd': {'di': 15000000, 'cy': 16800000, 'bob': 16800000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'di': 12345, 'cy': 0, 'bob': 5000}}, {'wage_expense': 181234, 'tax_expense': 13865, 'cash': 104339, 'withholding': 61070, 'benefits': 29690}], ['control 2', {'gross': [['bob', 100000]], 'ytd': {'bob': 16800000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'bob': 5000}}, {'wage_expense': 100000, 'tax_expense': 5170, 'cash': 78430, 'withholding': 21740, 'benefits': 5000}], ['control 3', {'gross': [['bob', 100000], ['ann', 250000], ['bob', 80000]], 'ytd': {'bob': 0, 'ann': 15000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'bob': 5000, 'ann': 0}}, {'wage_expense': 430000, 'tax_expense': 32895, 'cash': 294705, 'withholding': 158190, 'benefits': 10000}], ['control 4', {'gross': [['di', 50000], ['ann', 50000], ['cy', 1234]], 'ytd': {'di': 16800000, 'ann': 16800000, 'cy': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'di': 12345, 'ann': 0, 'cy': 5000}}, {'wage_expense': 101234, 'tax_expense': 7745, 'cash': 67755, 'withholding': 23879, 'benefits': 17345}], ['control 5', {'gross': [['ann', 333333], ['di', 100000], ['bob', 1234]], 'ytd': {'ann': 0, 'di': 17000000, 'bob': 16800000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'ann': 12345, 'di': 5000, 'bob': 5000}}, {'wage_expense': 434567, 'tax_expense': 27045, 'cash': 343955, 'withholding': 95312, 'benefits': 22345}]], [['regression: year-to-date accumulation', {'gross': [['bob', 100000], ['ann', 50000], ['bob', 80000]], 'ytd': {'bob': 16800000, 'ann': 17000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'bob': 5000, 'ann': 0}}, {'wage_expense': 230000, 'tax_expense': 7055, 'cash': 186545, 'withholding': 40510, 'benefits': 10000}], ['regression: year-to-date accumulation, partial-repair probe', {'gross': [['cy', 1234], ['bob', 100000], ['di', 250000], ['cy', 200000]], 'ytd': {'cy': 16800000, 'bob': 15000000, 'di': 15000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'cy': 12345, 'bob': 12345, 'di': 12345}}, {'wage_expense': 551234, 'tax_expense': 33413, 'cash': 408217, 'withholding': 127050, 'benefits': 49380}], ['control 1', {'gross': [['ann', 1234], ['bob', 100000], ['di', 50000], ['ann', 80000]], 'ytd': {'ann': 15000000, 'bob': 0, 'di': 17000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'ann': 0, 'bob': 12345, 'di': 12345}}, {'wage_expense': 231234, 'tax_expense': 14590, 'cash': 146515, 'withholding': 74619, 'benefits': 24690}], ['control 2', {'gross': [['cy', 50000], ['ann', 50000], ['di', 333333]], 'ytd': {'cy': 16700000, 'ann': 15000000, 'di': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'cy': 0, 'ann': 12345, 'di': 12345}}, {'wage_expense': 433333, 'tax_expense': 33150, 'cash': 334628, 'withholding': 107165, 'benefits': 24690}], ['control 3', {'gross': [['bob', 100000], ['ann', 250000]], 'ytd': {'bob': 15000000, 'ann': 15000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'bob': 12345, 'ann': 5000}}, {'wage_expense': 350000, 'tax_expense': 26775, 'cash': 272614, 'withholding': 86816, 'benefits': 17345}], ['control 4', {'gross': [['di', 100000], ['cy', 50000]], 'ytd': {'di': 16800000, 'cy': 16800000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'di': 12345, 'cy': 5000}}, {'wage_expense': 150000, 'tax_expense': 8995, 'cash': 94476, 'withholding': 47174, 'benefits': 17345}], ['control 5', {'gross': [['ann', 1234], ['bob', 1234], ['cy', 1234], ['ann', 80000]], 'ytd': {'ann': 0, 'bob': 16800000, 'cy': 17000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'ann': 12345, 'bob': 0, 'cy': 5000}}, {'wage_expense': 83702, 'tax_expense': 6328, 'cash': 41202, 'withholding': 19138, 'benefits': 29690}]], [['regression: year-to-date accumulation', {'gross': [['di', 250000], ['ann', 250000], ['di', 200000]], 'ytd': {'di': 16800000, 'ann': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'di': 12345, 'ann': 5000}}, {'wage_expense': 700000, 'tax_expense': 29370, 'cash': 560502, 'withholding': 139178, 'benefits': 29690}], ['regression: year-to-date accumulation, partial-repair probe', {'gross': [['cy', 50000], ['bob', 50000], ['cy', 200000]], 'ytd': {'cy': 16800000, 'bob': 16700000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'cy': 12345, 'bob': 12345}}, {'wage_expense': 300000, 'tax_expense': 11170, 'cash': 193943, 'withholding': 80192, 'benefits': 37035}], ['control 1', {'gross': [['ann', 250000], ['di', 333333], ['ann', 200000]], 'ytd': {'ann': 17000000, 'di': 15000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'ann': 5000, 'di': 12345}}, {'wage_expense': 783333, 'tax_expense': 32025, 'cash': 652864, 'withholding': 140149, 'benefits': 22345}], ['control 2', {'gross': [['ann', 50000], ['cy', 50000], ['bob', 100000]], 'ytd': {'ann': 0, 'cy': 0, 'bob': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'ann': 5000, 'cy': 5000, 'bob': 5000}}, {'wage_expense': 200000, 'tax_expense': 15300, 'cash': 147500, 'withholding': 52800, 'benefits': 15000}], ['control 3', {'gross': [['ann', 333333]], 'ytd': {'ann': 17000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'ann': 12345}}, {'wage_expense': 333333, 'tax_expense': 4833, 'cash': 284056, 'withholding': 41765, 'benefits': 12345}], ['control 4', {'gross': [['di', 50000], ['cy', 50000]], 'ytd': {'di': 16800000, 'cy': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'di': 5000, 'cy': 5000}}, {'wage_expense': 100000, 'tax_expense': 7650, 'cash': 71550, 'withholding': 26100, 'benefits': 10000}], ['control 5', {'gross': [['di', 250000], ['bob', 100000], ['cy', 1234], ['di', 200000]], 'ytd': {'di': 17000000, 'bob': 15000000, 'cy': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'di': 0, 'bob': 12345, 'cy': 5000}}, {'wage_expense': 551234, 'tax_expense': 14270, 'cash': 402164, 'withholding': 145995, 'benefits': 17345}]], [['regression: year-to-date accumulation', {'gross': [['bob', 1234], ['cy', 100000], ['ann', 100000], ['bob', 80000]], 'ytd': {'bob': 16800000, 'cy': 0, 'ann': 17000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'bob': 0, 'cy': 12345, 'ann': 5000}}, {'wage_expense': 281234, 'tax_expense': 13998, 'cash': 218224, 'withholding': 59663, 'benefits': 17345}], ['regression: year-to-date accumulation, partial-repair probe', {'gross': [['di', 100000], ['bob', 333333], ['ann', 250000], ['di', 200000]], 'ytd': {'di': 16700000, 'bob': 16700000, 'ann': 15000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'di': 5000, 'bob': 0, 'ann': 12345}}, {'wage_expense': 883333, 'tax_expense': 48148, 'cash': 709521, 'withholding': 199615, 'benefits': 22345}], ['control 1', {'gross': [['bob', 100000]], 'ytd': {'bob': 15000000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'bob': 5000}}, {'wage_expense': 100000, 'tax_expense': 7650, 'cash': 77850, 'withholding': 24800, 'benefits': 5000}], ['control 2', {'gross': [['ann', 100000], ['bob', 100000], ['cy', 250000]], 'ytd': {'ann': 16700000, 'bob': 17000000, 'cy': 16700000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'ann': 12345, 'bob': 5000, 'cy': 0}}, {'wage_expense': 450000, 'tax_expense': 22645, 'cash': 314826, 'withholding': 140474, 'benefits': 17345}], ['control 3', {'gross': [['cy', 100000]], 'ytd': {'cy': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'cy': 5000}}, {'wage_expense': 100000, 'tax_expense': 7650, 'cash': 77850, 'withholding': 24800, 'benefits': 5000}], ['control 4', {'gross': [['di', 100000], ['bob', 333333]], 'ytd': {'di': 0, 'bob': 16700000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'di': 0, 'bob': 12345}}, {'wage_expense': 433333, 'tax_expense': 22403, 'cash': 356486, 'withholding': 86905, 'benefits': 12345}], ['control 5', {'gross': [['bob', 333333], ['di', 250000], ['ann', 50000], ['bob', 80000]], 'ytd': {'bob': 0, 'di': 16700000, 'ann': 16700000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'bob': 12345, 'di': 0, 'ann': 5000}}, {'wage_expense': 713333, 'tax_expense': 48990, 'cash': 566288, 'withholding': 166345, 'benefits': 29690}]], [['regression: year-to-date accumulation', {'gross': [['bob', 50000], ['bob', 200000]], 'ytd': {'bob': 16800000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'bob': 5000}}, {'wage_expense': 250000, 'tax_expense': 7345, 'cash': 208655, 'withholding': 38690, 'benefits': 10000}], ['control 1', {'gross': [['ann', 333333], ['bob', 250000], ['cy', 1234]], 'ytd': {'ann': 0, 'bob': 16700000, 'cy': 16800000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'ann': 5000, 'bob': 12345, 'cy': 0}}, {'wage_expense': 584567, 'tax_expense': 39140, 'cash': 403294, 'withholding': 203068, 'benefits': 17345}], ['control 2', {'gross': [['di', 1234], ['bob', 333333], ['di', 80000]], 'ytd': {'di': 15000000, 'bob': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 2200, 'benefit': {'di': 0, 'bob': 0}}, {'wage_expense': 414567, 'tax_expense': 31715, 'cash': 291648, 'withholding': 154634, 'benefits': 0}], ['control 3', {'gross': [['di', 250000], ['di', 80000]], 'ytd': {'di': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'di': 5000}}, {'wage_expense': 330000, 'tax_expense': 25245, 'cash': 256355, 'withholding': 88890, 'benefits': 10000}], ['control 4', {'gross': [['di', 333333], ['bob', 100000], ['ann', 250000], ['di', 200000]], 'ytd': {'di': 17000000, 'bob': 17000000, 'ann': 16700000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'di': 5000, 'bob': 12345, 'ann': 12345}}, {'wage_expense': 883333, 'tax_expense': 22728, 'cash': 741050, 'withholding': 130321, 'benefits': 34690}], ['control 5', {'gross': [['bob', 100000], ['cy', 50000], ['ann', 100000]], 'ytd': {'bob': 15000000, 'cy': 16700000, 'ann': 16800000}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1000, 'benefit': {'bob': 0, 'cy': 5000, 'ann': 12345}}, {'wage_expense': 250000, 'tax_expense': 16645, 'cash': 192744, 'withholding': 56556, 'benefits': 17345}], ['control 6', {'gross': [['di', 1234]], 'ytd': {'di': 0}, 'wage_base': 16860000, 'ss_bp': 620, 'med_bp': 145, 'itax_bp': 1200, 'benefit': {'di': 5000}}, {'wage_expense': 1234, 'tax_expense': 95, 'cash': -3409, 'withholding': -262, 'benefits': 5000}]]]
for label, args, expected in fixtures[N-1]:
    try:
        actual = solve(args)
    except Exception as exc:
        actual = 'raised ' + type(exc).__name__
    check(label, actual, expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
regression: year-to-date accumulation{'benefits': 24690, 'cash': 560544, 'tax_expense': 31198, 'wage_expense': 783333, 'withholding': 229297}{'benefits': 24690, 'cash': 560544, 'tax_expense': 31198, 'wage_expense': 783333, 'withholding': 229297}Passed
regression: year-to-date accumulation, partial-repair probe{'benefits': 22345, 'cash': 148406, 'tax_expense': 13565, 'wage_expense': 230000, 'withholding': 72814}{'benefits': 22345, 'cash': 148716, 'tax_expense': 13255, 'wage_expense': 230000, 'withholding': 72194}Failed
control 1{'benefits': 29690, 'cash': 104339, 'tax_expense': 13865, 'wage_expense': 181234, 'withholding': 61070}{'benefits': 29690, 'cash': 104339, 'tax_expense': 13865, 'wage_expense': 181234, 'withholding': 61070}Passed
control 2{'benefits': 5000, 'cash': 78430, 'tax_expense': 5170, 'wage_expense': 100000, 'withholding': 21740}{'benefits': 5000, 'cash': 78430, 'tax_expense': 5170, 'wage_expense': 100000, 'withholding': 21740}Passed
control 3{'benefits': 10000, 'cash': 294705, 'tax_expense': 32895, 'wage_expense': 430000, 'withholding': 158190}{'benefits': 10000, 'cash': 294705, 'tax_expense': 32895, 'wage_expense': 430000, 'withholding': 158190}Passed
control 4{'benefits': 17345, 'cash': 67755, 'tax_expense': 7745, 'wage_expense': 101234, 'withholding': 23879}{'benefits': 17345, 'cash': 67755, 'tax_expense': 7745, 'wage_expense': 101234, 'withholding': 23879}Passed
control 5{'benefits': 22345, 'cash': 343955, 'tax_expense': 27045, 'wage_expense': 434567, 'withholding': 95312}{'benefits': 22345, 'cash': 343955, 'tax_expense': 27045, 'wage_expense': 434567, 'withholding': 95312}Passed

SHA-256 / 567c8967fcf8f4928856931f3eb3219eff220996df36f9ca2f544735bef88097

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 7 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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Verification & scope

A deterministic bounded teaching model with stipulated toy bookkeeping rules stated in the contract; amounts are integer cents; it makes no claim of conformance to any accounting standard or product. 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.

Observations recorded using Python 3.12.14 at 2026-09-29T14:46:25.311047+00:00.

Case digest / ba616b85081d60f34535c1aae196126b263301696dbff35ff5413555120fb007