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FA-59271 / Payroll withholding rules / Open access

Employment tax deposit due date: next-day threshold · case 01

Employers accumulating exactly 100,000 miss the next-day deposit.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The next-day rule requires strictly more than 100,000.00.

VERIFIED REPAIR

Restore the contract rule at the next-day threshold step: use `if x['accumulated'] >= 10000000:`.

Unsuccessful approach: The attempt tests lookback liability instead of liability accumulated for this payday.

Case contract

Input {pay_date, lookback_total, accumulated}. If accumulated liability is 100,000.00 or more, deposit the next weekday after pay date. Else if lookback liability is 50,000.00 or less, deposit monthly by the 15th of the following month. Else semiweekly: Wed/Thu/Fri paydays deposit the following Wednesday; Sat-Tue paydays the following Friday. Return [schedule, ISO due date].

Why this case matters

Deposit schedules depend on lookback liability and weekday of payment; a wrong due date means penalties.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import datetime
N = 1
observations = []
def solve(x):
    d = datetime.date(*x['pay_date'])
    if x['accumulated'] > 10000000:
        nd = d + datetime.timedelta(days=1)
        while nd.weekday() >= 5:
            nd += datetime.timedelta(days=1)
        return ['next-day', nd.isoformat()]
    if x['lookback_total'] <= 5000000:
        y, m = (d.year + 1, 1) if d.month == 12 else (d.year, d.month + 1)
        return ['monthly', datetime.date(y, m, 15).isoformat()]
    wd = d.weekday()
    if wd in (2, 3, 4):
        delta = (2 - wd) % 7 or 7
    else:
        delta = (4 - wd) % 7
    return ['semiweekly', (d + datetime.timedelta(days=delta)).isoformat()]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression', {'pay_date': [2026, 1, 10], 'lookback_total': 8559426, 'accumulated': 10000000}, ['next-day', '2026-01-12']), ('regression', {'pay_date': [2025, 7, 6], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-07']), ('partial-repair probe', {'pay_date': [2026, 1, 1], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2026-01-02']), ('partial-repair probe', {'pay_date': [2025, 7, 12], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-14']), ('normal control', {'pay_date': [2025, 7, 24], 'lookback_total': 5000000, 'accumulated': 9999999}, ['monthly', '2025-08-15']), ('normal control', {'pay_date': [2025, 7, 23], 'lookback_total': 4030366, 'accumulated': 7676976}, ['monthly', '2025-08-15']), ('normal control', {'pay_date': [2025, 11, 30], 'lookback_total': 5000000, 'accumulated': 9999999}, ['monthly', '2025-12-15']), ('normal control', {'pay_date': [2025, 10, 17], 'lookback_total': 5000001, 'accumulated': 9999999}, ['semiweekly', '2025-10-22'])], [('regression', {'pay_date': [2025, 7, 6], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-07']), ('regression', {'pay_date': [2026, 1, 1], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2026-01-02']), ('partial-repair probe', {'pay_date': [2025, 7, 12], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-14']), ('partial-repair probe', {'pay_date': [2025, 8, 20], 'lookback_total': 15073801, 'accumulated': 1953477}, ['semiweekly', '2025-08-27']), ('normal control', {'pay_date': [2025, 3, 12], 'lookback_total': 5000000, 'accumulated': 5561044}, ['monthly', '2025-04-15']), ('normal control', {'pay_date': [2026, 1, 15], 'lookback_total': 5000001, 'accumulated': 128367}, ['semiweekly', '2026-01-21']), ('normal control', {'pay_date': [2024, 12, 14], 'lookback_total': 5000000, 'accumulated': 9999999}, ['monthly', '2025-01-15']), ('normal control', {'pay_date': [2025, 4, 9], 'lookback_total': 5000000, 'accumulated': 17594}, ['monthly', '2025-05-15'])], [('regression', {'pay_date': [2026, 1, 1], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2026-01-02']), ('regression', {'pay_date': [2025, 7, 12], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-14']), ('partial-repair probe', {'pay_date': [2025, 8, 20], 'lookback_total': 15073801, 'accumulated': 1953477}, ['semiweekly', '2025-08-27']), ('partial-repair probe', {'pay_date': [2024, 12, 27], 'lookback_total': 14968828, 'accumulated': 48129}, ['semiweekly', '2025-01-01']), ('normal control', {'pay_date': [2025, 1, 28], 'lookback_total': 5000001, 'accumulated': 2892395}, ['semiweekly', '2025-01-31']), ('normal control', {'pay_date': [2026, 1, 11], 'lookback_total': 5000000, 'accumulated': 106033}, ['monthly', '2026-02-15']), ('normal control', {'pay_date': [2025, 1, 9], 'lookback_total': 5000001, 'accumulated': 9999999}, ['semiweekly', '2025-01-15']), ('normal control', {'pay_date': [2025, 12, 21], 'lookback_total': 5000000, 'accumulated': 9999999}, ['monthly', '2026-01-15'])], [('regression', {'pay_date': [2025, 7, 12], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-14']), ('regression', {'pay_date': [2025, 2, 13], 'lookback_total': 2864521, 'accumulated': 10000000}, ['next-day', '2025-02-14']), ('partial-repair probe', {'pay_date': [2024, 12, 22], 'lookback_total': 5000001, 'accumulated': 10000000}, ['next-day', '2024-12-23']), ('partial-repair probe', {'pay_date': [2025, 1, 28], 'lookback_total': 14733386, 'accumulated': 9999999}, ['semiweekly', '2025-01-31']), ('normal control', {'pay_date': [2024, 12, 8], 'lookback_total': 7946403, 'accumulated': 200852}, ['semiweekly', '2024-12-13']), ('normal control', {'pay_date': [2025, 9, 18], 'lookback_total': 5000001, 'accumulated': 171509}, ['semiweekly', '2025-09-24']), ('normal control', {'pay_date': [2025, 7, 15], 'lookback_total': 7386577, 'accumulated': 7242712}, ['semiweekly', '2025-07-18']), ('normal control', {'pay_date': [2025, 6, 8], 'lookback_total': 5000001, 'accumulated': 136142}, ['semiweekly', '2025-06-13'])], [('regression', {'pay_date': [2025, 2, 13], 'lookback_total': 2864521, 'accumulated': 10000000}, ['next-day', '2025-02-14']), ('regression', {'pay_date': [2024, 12, 22], 'lookback_total': 5000001, 'accumulated': 10000000}, ['next-day', '2024-12-23']), ('partial-repair probe', {'pay_date': [2025, 1, 28], 'lookback_total': 14733386, 'accumulated': 9999999}, ['semiweekly', '2025-01-31']), ('partial-repair probe', {'pay_date': [2025, 12, 8], 'lookback_total': 5000001, 'accumulated': 10000000}, ['next-day', '2025-12-09']), ('normal control', {'pay_date': [2025, 2, 28], 'lookback_total': 5934057, 'accumulated': 9999999}, ['semiweekly', '2025-03-05']), ('normal control', {'pay_date': [2025, 10, 25], 'lookback_total': 5000001, 'accumulated': 9999999}, ['semiweekly', '2025-10-31']), ('normal control', {'pay_date': [2024, 12, 12], 'lookback_total': 5000001, 'accumulated': 126127}, ['semiweekly', '2024-12-18']), ('normal control', {'pay_date': [2025, 7, 2], 'lookback_total': 5000000, 'accumulated': 9342050}, ['monthly', '2025-08-15'])]]
for i, (label, args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (label, i), solve(args), 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 0['semiweekly', '2026-01-16']['next-day', '2026-01-12']Failed
regression 1['monthly', '2025-08-15']['next-day', '2025-07-07']Failed
partial-repair probe 2['monthly', '2026-02-15']['next-day', '2026-01-02']Failed
partial-repair probe 3['monthly', '2025-08-15']['next-day', '2025-07-14']Failed
normal control 4['monthly', '2025-08-15']['monthly', '2025-08-15']Passed
normal control 5['monthly', '2025-08-15']['monthly', '2025-08-15']Passed
normal control 6['monthly', '2025-12-15']['monthly', '2025-12-15']Passed
normal control 7['semiweekly', '2025-10-22']['semiweekly', '2025-10-22']Passed

SHA-256 / 9461e611c747a27371618e8b9aa55ec90c523b77ba713d863e05a81223f48123

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import datetime
N = 1
observations = []
def solve(x):
    d = datetime.date(*x['pay_date'])
    if x['lookback_total'] >= 10000000:
        nd = d + datetime.timedelta(days=1)
        while nd.weekday() >= 5:
            nd += datetime.timedelta(days=1)
        return ['next-day', nd.isoformat()]
    if x['lookback_total'] <= 5000000:
        y, m = (d.year + 1, 1) if d.month == 12 else (d.year, d.month + 1)
        return ['monthly', datetime.date(y, m, 15).isoformat()]
    wd = d.weekday()
    if wd in (2, 3, 4):
        delta = (2 - wd) % 7 or 7
    else:
        delta = (4 - wd) % 7
    return ['semiweekly', (d + datetime.timedelta(days=delta)).isoformat()]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression', {'pay_date': [2026, 1, 10], 'lookback_total': 8559426, 'accumulated': 10000000}, ['next-day', '2026-01-12']), ('regression', {'pay_date': [2025, 7, 6], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-07']), ('partial-repair probe', {'pay_date': [2026, 1, 1], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2026-01-02']), ('partial-repair probe', {'pay_date': [2025, 7, 12], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-14']), ('normal control', {'pay_date': [2025, 7, 24], 'lookback_total': 5000000, 'accumulated': 9999999}, ['monthly', '2025-08-15']), ('normal control', {'pay_date': [2025, 7, 23], 'lookback_total': 4030366, 'accumulated': 7676976}, ['monthly', '2025-08-15']), ('normal control', {'pay_date': [2025, 11, 30], 'lookback_total': 5000000, 'accumulated': 9999999}, ['monthly', '2025-12-15']), ('normal control', {'pay_date': [2025, 10, 17], 'lookback_total': 5000001, 'accumulated': 9999999}, ['semiweekly', '2025-10-22'])], [('regression', {'pay_date': [2025, 7, 6], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-07']), ('regression', {'pay_date': [2026, 1, 1], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2026-01-02']), ('partial-repair probe', {'pay_date': [2025, 7, 12], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-14']), ('partial-repair probe', {'pay_date': [2025, 8, 20], 'lookback_total': 15073801, 'accumulated': 1953477}, ['semiweekly', '2025-08-27']), ('normal control', {'pay_date': [2025, 3, 12], 'lookback_total': 5000000, 'accumulated': 5561044}, ['monthly', '2025-04-15']), ('normal control', {'pay_date': [2026, 1, 15], 'lookback_total': 5000001, 'accumulated': 128367}, ['semiweekly', '2026-01-21']), ('normal control', {'pay_date': [2024, 12, 14], 'lookback_total': 5000000, 'accumulated': 9999999}, ['monthly', '2025-01-15']), ('normal control', {'pay_date': [2025, 4, 9], 'lookback_total': 5000000, 'accumulated': 17594}, ['monthly', '2025-05-15'])], [('regression', {'pay_date': [2026, 1, 1], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2026-01-02']), ('regression', {'pay_date': [2025, 7, 12], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-14']), ('partial-repair probe', {'pay_date': [2025, 8, 20], 'lookback_total': 15073801, 'accumulated': 1953477}, ['semiweekly', '2025-08-27']), ('partial-repair probe', {'pay_date': [2024, 12, 27], 'lookback_total': 14968828, 'accumulated': 48129}, ['semiweekly', '2025-01-01']), ('normal control', {'pay_date': [2025, 1, 28], 'lookback_total': 5000001, 'accumulated': 2892395}, ['semiweekly', '2025-01-31']), ('normal control', {'pay_date': [2026, 1, 11], 'lookback_total': 5000000, 'accumulated': 106033}, ['monthly', '2026-02-15']), ('normal control', {'pay_date': [2025, 1, 9], 'lookback_total': 5000001, 'accumulated': 9999999}, ['semiweekly', '2025-01-15']), ('normal control', {'pay_date': [2025, 12, 21], 'lookback_total': 5000000, 'accumulated': 9999999}, ['monthly', '2026-01-15'])], [('regression', {'pay_date': [2025, 7, 12], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-14']), ('regression', {'pay_date': [2025, 2, 13], 'lookback_total': 2864521, 'accumulated': 10000000}, ['next-day', '2025-02-14']), ('partial-repair probe', {'pay_date': [2024, 12, 22], 'lookback_total': 5000001, 'accumulated': 10000000}, ['next-day', '2024-12-23']), ('partial-repair probe', {'pay_date': [2025, 1, 28], 'lookback_total': 14733386, 'accumulated': 9999999}, ['semiweekly', '2025-01-31']), ('normal control', {'pay_date': [2024, 12, 8], 'lookback_total': 7946403, 'accumulated': 200852}, ['semiweekly', '2024-12-13']), ('normal control', {'pay_date': [2025, 9, 18], 'lookback_total': 5000001, 'accumulated': 171509}, ['semiweekly', '2025-09-24']), ('normal control', {'pay_date': [2025, 7, 15], 'lookback_total': 7386577, 'accumulated': 7242712}, ['semiweekly', '2025-07-18']), ('normal control', {'pay_date': [2025, 6, 8], 'lookback_total': 5000001, 'accumulated': 136142}, ['semiweekly', '2025-06-13'])], [('regression', {'pay_date': [2025, 2, 13], 'lookback_total': 2864521, 'accumulated': 10000000}, ['next-day', '2025-02-14']), ('regression', {'pay_date': [2024, 12, 22], 'lookback_total': 5000001, 'accumulated': 10000000}, ['next-day', '2024-12-23']), ('partial-repair probe', {'pay_date': [2025, 1, 28], 'lookback_total': 14733386, 'accumulated': 9999999}, ['semiweekly', '2025-01-31']), ('partial-repair probe', {'pay_date': [2025, 12, 8], 'lookback_total': 5000001, 'accumulated': 10000000}, ['next-day', '2025-12-09']), ('normal control', {'pay_date': [2025, 2, 28], 'lookback_total': 5934057, 'accumulated': 9999999}, ['semiweekly', '2025-03-05']), ('normal control', {'pay_date': [2025, 10, 25], 'lookback_total': 5000001, 'accumulated': 9999999}, ['semiweekly', '2025-10-31']), ('normal control', {'pay_date': [2024, 12, 12], 'lookback_total': 5000001, 'accumulated': 126127}, ['semiweekly', '2024-12-18']), ('normal control', {'pay_date': [2025, 7, 2], 'lookback_total': 5000000, 'accumulated': 9342050}, ['monthly', '2025-08-15'])]]
for i, (label, args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (label, i), solve(args), 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 0['semiweekly', '2026-01-16']['next-day', '2026-01-12']Failed
regression 1['monthly', '2025-08-15']['next-day', '2025-07-07']Failed
partial-repair probe 2['monthly', '2026-02-15']['next-day', '2026-01-02']Failed
partial-repair probe 3['monthly', '2025-08-15']['next-day', '2025-07-14']Failed
normal control 4['monthly', '2025-08-15']['monthly', '2025-08-15']Passed
normal control 5['monthly', '2025-08-15']['monthly', '2025-08-15']Passed
normal control 6['monthly', '2025-12-15']['monthly', '2025-12-15']Passed
normal control 7['semiweekly', '2025-10-22']['semiweekly', '2025-10-22']Passed

SHA-256 / 809e028a12123938863450cb76ee01b7bde7d3648edc2e7bfe05230b38b6592e

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json
import datetime
N = 1
observations = []
def solve(x):
    d = datetime.date(*x['pay_date'])
    if x['accumulated'] >= 10000000:
        nd = d + datetime.timedelta(days=1)
        while nd.weekday() >= 5:
            nd += datetime.timedelta(days=1)
        return ['next-day', nd.isoformat()]
    if x['lookback_total'] <= 5000000:
        y, m = (d.year + 1, 1) if d.month == 12 else (d.year, d.month + 1)
        return ['monthly', datetime.date(y, m, 15).isoformat()]
    wd = d.weekday()
    if wd in (2, 3, 4):
        delta = (2 - wd) % 7 or 7
    else:
        delta = (4 - wd) % 7
    return ['semiweekly', (d + datetime.timedelta(days=delta)).isoformat()]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression', {'pay_date': [2026, 1, 10], 'lookback_total': 8559426, 'accumulated': 10000000}, ['next-day', '2026-01-12']), ('regression', {'pay_date': [2025, 7, 6], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-07']), ('partial-repair probe', {'pay_date': [2026, 1, 1], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2026-01-02']), ('partial-repair probe', {'pay_date': [2025, 7, 12], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-14']), ('normal control', {'pay_date': [2025, 7, 24], 'lookback_total': 5000000, 'accumulated': 9999999}, ['monthly', '2025-08-15']), ('normal control', {'pay_date': [2025, 7, 23], 'lookback_total': 4030366, 'accumulated': 7676976}, ['monthly', '2025-08-15']), ('normal control', {'pay_date': [2025, 11, 30], 'lookback_total': 5000000, 'accumulated': 9999999}, ['monthly', '2025-12-15']), ('normal control', {'pay_date': [2025, 10, 17], 'lookback_total': 5000001, 'accumulated': 9999999}, ['semiweekly', '2025-10-22'])], [('regression', {'pay_date': [2025, 7, 6], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-07']), ('regression', {'pay_date': [2026, 1, 1], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2026-01-02']), ('partial-repair probe', {'pay_date': [2025, 7, 12], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-14']), ('partial-repair probe', {'pay_date': [2025, 8, 20], 'lookback_total': 15073801, 'accumulated': 1953477}, ['semiweekly', '2025-08-27']), ('normal control', {'pay_date': [2025, 3, 12], 'lookback_total': 5000000, 'accumulated': 5561044}, ['monthly', '2025-04-15']), ('normal control', {'pay_date': [2026, 1, 15], 'lookback_total': 5000001, 'accumulated': 128367}, ['semiweekly', '2026-01-21']), ('normal control', {'pay_date': [2024, 12, 14], 'lookback_total': 5000000, 'accumulated': 9999999}, ['monthly', '2025-01-15']), ('normal control', {'pay_date': [2025, 4, 9], 'lookback_total': 5000000, 'accumulated': 17594}, ['monthly', '2025-05-15'])], [('regression', {'pay_date': [2026, 1, 1], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2026-01-02']), ('regression', {'pay_date': [2025, 7, 12], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-14']), ('partial-repair probe', {'pay_date': [2025, 8, 20], 'lookback_total': 15073801, 'accumulated': 1953477}, ['semiweekly', '2025-08-27']), ('partial-repair probe', {'pay_date': [2024, 12, 27], 'lookback_total': 14968828, 'accumulated': 48129}, ['semiweekly', '2025-01-01']), ('normal control', {'pay_date': [2025, 1, 28], 'lookback_total': 5000001, 'accumulated': 2892395}, ['semiweekly', '2025-01-31']), ('normal control', {'pay_date': [2026, 1, 11], 'lookback_total': 5000000, 'accumulated': 106033}, ['monthly', '2026-02-15']), ('normal control', {'pay_date': [2025, 1, 9], 'lookback_total': 5000001, 'accumulated': 9999999}, ['semiweekly', '2025-01-15']), ('normal control', {'pay_date': [2025, 12, 21], 'lookback_total': 5000000, 'accumulated': 9999999}, ['monthly', '2026-01-15'])], [('regression', {'pay_date': [2025, 7, 12], 'lookback_total': 5000000, 'accumulated': 10000000}, ['next-day', '2025-07-14']), ('regression', {'pay_date': [2025, 2, 13], 'lookback_total': 2864521, 'accumulated': 10000000}, ['next-day', '2025-02-14']), ('partial-repair probe', {'pay_date': [2024, 12, 22], 'lookback_total': 5000001, 'accumulated': 10000000}, ['next-day', '2024-12-23']), ('partial-repair probe', {'pay_date': [2025, 1, 28], 'lookback_total': 14733386, 'accumulated': 9999999}, ['semiweekly', '2025-01-31']), ('normal control', {'pay_date': [2024, 12, 8], 'lookback_total': 7946403, 'accumulated': 200852}, ['semiweekly', '2024-12-13']), ('normal control', {'pay_date': [2025, 9, 18], 'lookback_total': 5000001, 'accumulated': 171509}, ['semiweekly', '2025-09-24']), ('normal control', {'pay_date': [2025, 7, 15], 'lookback_total': 7386577, 'accumulated': 7242712}, ['semiweekly', '2025-07-18']), ('normal control', {'pay_date': [2025, 6, 8], 'lookback_total': 5000001, 'accumulated': 136142}, ['semiweekly', '2025-06-13'])], [('regression', {'pay_date': [2025, 2, 13], 'lookback_total': 2864521, 'accumulated': 10000000}, ['next-day', '2025-02-14']), ('regression', {'pay_date': [2024, 12, 22], 'lookback_total': 5000001, 'accumulated': 10000000}, ['next-day', '2024-12-23']), ('partial-repair probe', {'pay_date': [2025, 1, 28], 'lookback_total': 14733386, 'accumulated': 9999999}, ['semiweekly', '2025-01-31']), ('partial-repair probe', {'pay_date': [2025, 12, 8], 'lookback_total': 5000001, 'accumulated': 10000000}, ['next-day', '2025-12-09']), ('normal control', {'pay_date': [2025, 2, 28], 'lookback_total': 5934057, 'accumulated': 9999999}, ['semiweekly', '2025-03-05']), ('normal control', {'pay_date': [2025, 10, 25], 'lookback_total': 5000001, 'accumulated': 9999999}, ['semiweekly', '2025-10-31']), ('normal control', {'pay_date': [2024, 12, 12], 'lookback_total': 5000001, 'accumulated': 126127}, ['semiweekly', '2024-12-18']), ('normal control', {'pay_date': [2025, 7, 2], 'lookback_total': 5000000, 'accumulated': 9342050}, ['monthly', '2025-08-15'])]]
for i, (label, args, expected) in enumerate(fixtures[N-1]):
    check("%s %d" % (label, i), solve(args), 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 0['next-day', '2026-01-12']['next-day', '2026-01-12']Passed
regression 1['next-day', '2025-07-07']['next-day', '2025-07-07']Passed
partial-repair probe 2['next-day', '2026-01-02']['next-day', '2026-01-02']Passed
partial-repair probe 3['next-day', '2025-07-14']['next-day', '2025-07-14']Passed
normal control 4['monthly', '2025-08-15']['monthly', '2025-08-15']Passed
normal control 5['monthly', '2025-08-15']['monthly', '2025-08-15']Passed
normal control 6['monthly', '2025-12-15']['monthly', '2025-12-15']Passed
normal control 7['semiweekly', '2025-10-22']['semiweekly', '2025-10-22']Passed

SHA-256 / ea268a5b5995459d9a638774d05c74a51e98a704254b07d52f5ee9dd831163b1

Verification & scope

A deterministic teaching model of a stipulated payroll rule with toy thresholds and rates. It makes no claim of conformance to any tax authority, statute or jurisdiction and is not payroll 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.

Observations recorded using Python 3.12.14 at 2026-09-29T14:46:34.762399+00:00.

Case digest / 0a52e977284e3f290a933cd688ca9870e72aaae0e17f3e650ef9eb9d287d79d5