FA-62176 / Currency rounding and FX conversion / Open access

Spot is computed as two calendar days and then rolled forward · case 01

A Thursday trade settles on Monday only by accident; a Friday trade settles Monday instead of Tuesday.

Verified by executionVariant 1 · 7 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The lag is added in calendar days and the result is rolled to the next good day.

VERIFIED REPAIR

Count the lag in business days, applying the intermediate and final-day rules.

Unsuccessful approach: Counting weekdays but ignoring holidays on intermediate days still undercounts around non-USD holidays.

Case contract

solve(trade, pair, holidays): stipulated spot value-date rule. USDCAD/CADUSD settle T+1, every other pair T+2. Count forward from the trade date: a day before the final one counts only if it is a weekday and not a holiday of the non-USD currencies of the pair; the value date itself must be a weekday that is a holiday in neither currency. holidays maps currency to ISO date strings. Return the ISO value date.

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.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
from datetime import date, timedelta
N = 1
observations = []
def solve(trade, pair, holidays):
    d = date.fromisoformat(trade)
    base, quote = pair[:3], pair[3:]
    def good(x, ccys):
        return x.weekday() < 5 and all(x.isoformat() not in holidays.get(c, []) for c in ccys)
    lag = 1 if {base, quote} == {'USD', 'CAD'} else 2
    non_usd = [c for c in (base, quote) if c != 'USD']
    x = d + timedelta(days=lag)
    while not good(x, [base, quote]): x += timedelta(days=1)
    return x.isoformat()
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('regression business-day-counting 1', ('2026-03-06', 'EURUSD', {}), '2026-03-10'),
  ('regression business-day-counting 2', ('2026-03-02', 'EURUSD', {'EUR': ['2026-03-03']}), '2026-03-05'),
  ('partial repair guard 2', ('2026-04-28', 'GBPJPY', {'JPY': ['2026-04-29', '2026-04-30']}), '2026-05-04'),
  ('control: plain t+2', ('2026-03-02', 'EURUSD', {}), '2026-03-04'),
  ('control: over weekend', ('2026-03-05', 'EURUSD', {}), '2026-03-09'),
  ('control: usd holiday t+1', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-03']}), '2026-03-04'),
  ('control: usd holiday on spot', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-04']}), '2026-03-05')],
 [('regression business-day-counting 1', ('2026-04-28', 'GBPJPY', {'JPY': ['2026-04-29', '2026-04-30']}), '2026-05-04'),
  ('regression business-day-counting 2',
   ('2026-03-30', 'EURGBP', {'EUR': ['2026-03-31', '2026-04-04'], 'CAD': ['2026-04-02'], 'GBP': ['2026-04-03']}),
   '2026-04-02'),
  ('partial repair guard 2',
   ('2026-10-09', 'GBPJPY',
    {'JPY': ['2026-10-11', '2026-10-12', '2026-10-13'],
     'EUR': ['2026-10-14'],
     'CAD': ['2026-10-10', '2026-10-11', '2026-10-12', '2026-10-13'],
     'GBP': ['2026-10-12', '2026-10-14']}),
   '2026-10-16'),
  ('control: usd holiday on spot', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-04']}), '2026-03-05'),
  ('control: cad t+1', ('2026-03-02', 'USDCAD', {}), '2026-03-03'),
  ('control: euro holiday t+1', ('2026-03-02', 'EURUSD', {'EUR': ['2026-03-03']}), '2026-03-05'),
  ('control: cross with cad', ('2026-03-02', 'EURCAD', {}), '2026-03-04')],
 [('regression business-day-counting 1',
   ('2026-10-09', 'GBPJPY',
    {'JPY': ['2026-10-11', '2026-10-12', '2026-10-13'],
     'EUR': ['2026-10-14'],
     'CAD': ['2026-10-10', '2026-10-11', '2026-10-12', '2026-10-13'],
     'GBP': ['2026-10-12', '2026-10-14']}),
   '2026-10-16'),
  ('regression business-day-counting 2',
   ('2026-08-14', 'GBPJPY',
    {'USD': [], 'JPY': ['2026-08-15', '2026-08-17', '2026-08-19'], 'EUR': ['2026-08-15', '2026-08-17']}),
   '2026-08-20'),
  ('partial repair guard 2',
   ('2026-07-22', 'EURUSD', {'EUR': ['2026-07-23', '2026-07-24', '2026-07-25'], 'CAD': ['2026-07-23', '2026-07-26']}),
   '2026-07-28'),
  ('control: cross with cad', ('2026-03-02', 'EURCAD', {}), '2026-03-04'),
  ('control: cad usd holiday', ('2026-03-06', 'CADUSD', {'USD': ['2026-03-09']}), '2026-03-10'),
  ('control: yen cross', ('2026-04-28', 'GBPJPY', {'JPY': ['2026-04-29', '2026-04-30']}), '2026-05-04'),
  ('control: plain t+2', ('2026-03-02', 'EURUSD', {}), '2026-03-04')],
 [('regression business-day-counting 1',
   ('2026-07-22', 'EURUSD', {'EUR': ['2026-07-23', '2026-07-24', '2026-07-25'], 'CAD': ['2026-07-23', '2026-07-26']}),
   '2026-07-28'),
  ('regression business-day-counting 2',
   ('2026-02-16', 'EURCAD',
    {'USD': ['2026-02-17', '2026-02-18', '2026-02-20'],
     'EUR': ['2026-02-17', '2026-02-21'],
     'CAD': [],
     'GBP': ['2026-02-17', '2026-02-20']}),
   '2026-02-19'),
  ('partial repair guard 2',
   ('2026-03-23', 'EURCAD',
    {'JPY': ['2026-03-27'], 'EUR': ['2026-03-25'], 'CAD': ['2026-03-24', '2026-03-26'], 'GBP': ['2026-03-25']}),
   '2026-03-30'),
  ('control: plain t+2', ('2026-03-02', 'EURUSD', {}), '2026-03-04'),
  ('control: over weekend', ('2026-03-05', 'EURUSD', {}), '2026-03-09'),
  ('control: usd holiday t+1', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-03']}), '2026-03-04'),
  ('control: usd holiday on spot', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-04']}), '2026-03-05')],
 [('regression business-day-counting 1',
   ('2026-03-23', 'EURCAD',
    {'JPY': ['2026-03-27'], 'EUR': ['2026-03-25'], 'CAD': ['2026-03-24', '2026-03-26'], 'GBP': ['2026-03-25']}),
   '2026-03-30'),
  ('regression business-day-counting 2',
   ('2026-08-28', 'EURCAD',
    {'USD': ['2026-08-30', '2026-08-31', '2026-09-01'],
     'EUR': ['2026-08-31', '2026-09-01'],
     'CAD': ['2026-08-29', '2026-08-31'],
     'GBP': ['2026-08-29', '2026-09-01']}),
   '2026-09-03'),
  ('partial repair guard 2',
   ('2026-03-19', 'EURCAD', {'USD': ['2026-03-21'], 'JPY': ['2026-03-20'], 'EUR': ['2026-03-20'], 'CAD': []}),
   '2026-03-24'),
  ('control: usd holiday on spot', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-04']}), '2026-03-05'),
  ('control: cad t+1', ('2026-03-02', 'USDCAD', {}), '2026-03-03'),
  ('control: euro holiday t+1', ('2026-03-02', 'EURUSD', {'EUR': ['2026-03-03']}), '2026-03-05'),
  ('control: cross with cad', ('2026-03-02', 'EURCAD', {}), '2026-03-04')]]
for label, args, expected in cases[N - 1]:
    check(label, 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 fixture	Actual	Expected	Outcome
regression business-day-counting 1	`2026-03-09`	`2026-03-10`	Failed
regression business-day-counting 2	`2026-03-04`	`2026-03-05`	Failed
partial repair guard 2	`2026-05-01`	`2026-05-04`	Failed
control: plain t+2	`2026-03-04`	`2026-03-04`	Passed
control: over weekend	`2026-03-09`	`2026-03-09`	Passed
control: usd holiday t+1	`2026-03-04`	`2026-03-04`	Passed
control: usd holiday on spot	`2026-03-05`	`2026-03-05`	Passed

SHA-256 / 9b77750f9f27ea4f43a9b687a749ae54d8f35b0f49f9d4f1219178a51ec4fc2b

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
from datetime import date, timedelta
N = 1
observations = []
def solve(trade, pair, holidays):
    d = date.fromisoformat(trade)
    base, quote = pair[:3], pair[3:]
    def good(x, ccys):
        return x.weekday() < 5 and all(x.isoformat() not in holidays.get(c, []) for c in ccys)
    lag = 1 if {base, quote} == {'USD', 'CAD'} else 2
    non_usd = [c for c in (base, quote) if c != 'USD']
    x, n = d, 0
    while n < lag:
        x += timedelta(days=1)
        if x.weekday() < 5: n += 1
    while not good(x, [base, quote]): x += timedelta(days=1)
    return x.isoformat()
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('regression business-day-counting 1', ('2026-03-06', 'EURUSD', {}), '2026-03-10'),
  ('regression business-day-counting 2', ('2026-03-02', 'EURUSD', {'EUR': ['2026-03-03']}), '2026-03-05'),
  ('partial repair guard 2', ('2026-04-28', 'GBPJPY', {'JPY': ['2026-04-29', '2026-04-30']}), '2026-05-04'),
  ('control: plain t+2', ('2026-03-02', 'EURUSD', {}), '2026-03-04'),
  ('control: over weekend', ('2026-03-05', 'EURUSD', {}), '2026-03-09'),
  ('control: usd holiday t+1', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-03']}), '2026-03-04'),
  ('control: usd holiday on spot', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-04']}), '2026-03-05')],
 [('regression business-day-counting 1', ('2026-04-28', 'GBPJPY', {'JPY': ['2026-04-29', '2026-04-30']}), '2026-05-04'),
  ('regression business-day-counting 2',
   ('2026-03-30', 'EURGBP', {'EUR': ['2026-03-31', '2026-04-04'], 'CAD': ['2026-04-02'], 'GBP': ['2026-04-03']}),
   '2026-04-02'),
  ('partial repair guard 2',
   ('2026-10-09', 'GBPJPY',
    {'JPY': ['2026-10-11', '2026-10-12', '2026-10-13'],
     'EUR': ['2026-10-14'],
     'CAD': ['2026-10-10', '2026-10-11', '2026-10-12', '2026-10-13'],
     'GBP': ['2026-10-12', '2026-10-14']}),
   '2026-10-16'),
  ('control: usd holiday on spot', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-04']}), '2026-03-05'),
  ('control: cad t+1', ('2026-03-02', 'USDCAD', {}), '2026-03-03'),
  ('control: euro holiday t+1', ('2026-03-02', 'EURUSD', {'EUR': ['2026-03-03']}), '2026-03-05'),
  ('control: cross with cad', ('2026-03-02', 'EURCAD', {}), '2026-03-04')],
 [('regression business-day-counting 1',
   ('2026-10-09', 'GBPJPY',
    {'JPY': ['2026-10-11', '2026-10-12', '2026-10-13'],
     'EUR': ['2026-10-14'],
     'CAD': ['2026-10-10', '2026-10-11', '2026-10-12', '2026-10-13'],
     'GBP': ['2026-10-12', '2026-10-14']}),
   '2026-10-16'),
  ('regression business-day-counting 2',
   ('2026-08-14', 'GBPJPY',
    {'USD': [], 'JPY': ['2026-08-15', '2026-08-17', '2026-08-19'], 'EUR': ['2026-08-15', '2026-08-17']}),
   '2026-08-20'),
  ('partial repair guard 2',
   ('2026-07-22', 'EURUSD', {'EUR': ['2026-07-23', '2026-07-24', '2026-07-25'], 'CAD': ['2026-07-23', '2026-07-26']}),
   '2026-07-28'),
  ('control: cross with cad', ('2026-03-02', 'EURCAD', {}), '2026-03-04'),
  ('control: cad usd holiday', ('2026-03-06', 'CADUSD', {'USD': ['2026-03-09']}), '2026-03-10'),
  ('control: yen cross', ('2026-04-28', 'GBPJPY', {'JPY': ['2026-04-29', '2026-04-30']}), '2026-05-04'),
  ('control: plain t+2', ('2026-03-02', 'EURUSD', {}), '2026-03-04')],
 [('regression business-day-counting 1',
   ('2026-07-22', 'EURUSD', {'EUR': ['2026-07-23', '2026-07-24', '2026-07-25'], 'CAD': ['2026-07-23', '2026-07-26']}),
   '2026-07-28'),
  ('regression business-day-counting 2',
   ('2026-02-16', 'EURCAD',
    {'USD': ['2026-02-17', '2026-02-18', '2026-02-20'],
     'EUR': ['2026-02-17', '2026-02-21'],
     'CAD': [],
     'GBP': ['2026-02-17', '2026-02-20']}),
   '2026-02-19'),
  ('partial repair guard 2',
   ('2026-03-23', 'EURCAD',
    {'JPY': ['2026-03-27'], 'EUR': ['2026-03-25'], 'CAD': ['2026-03-24', '2026-03-26'], 'GBP': ['2026-03-25']}),
   '2026-03-30'),
  ('control: plain t+2', ('2026-03-02', 'EURUSD', {}), '2026-03-04'),
  ('control: over weekend', ('2026-03-05', 'EURUSD', {}), '2026-03-09'),
  ('control: usd holiday t+1', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-03']}), '2026-03-04'),
  ('control: usd holiday on spot', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-04']}), '2026-03-05')],
 [('regression business-day-counting 1',
   ('2026-03-23', 'EURCAD',
    {'JPY': ['2026-03-27'], 'EUR': ['2026-03-25'], 'CAD': ['2026-03-24', '2026-03-26'], 'GBP': ['2026-03-25']}),
   '2026-03-30'),
  ('regression business-day-counting 2',
   ('2026-08-28', 'EURCAD',
    {'USD': ['2026-08-30', '2026-08-31', '2026-09-01'],
     'EUR': ['2026-08-31', '2026-09-01'],
     'CAD': ['2026-08-29', '2026-08-31'],
     'GBP': ['2026-08-29', '2026-09-01']}),
   '2026-09-03'),
  ('partial repair guard 2',
   ('2026-03-19', 'EURCAD', {'USD': ['2026-03-21'], 'JPY': ['2026-03-20'], 'EUR': ['2026-03-20'], 'CAD': []}),
   '2026-03-24'),
  ('control: usd holiday on spot', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-04']}), '2026-03-05'),
  ('control: cad t+1', ('2026-03-02', 'USDCAD', {}), '2026-03-03'),
  ('control: euro holiday t+1', ('2026-03-02', 'EURUSD', {'EUR': ['2026-03-03']}), '2026-03-05'),
  ('control: cross with cad', ('2026-03-02', 'EURCAD', {}), '2026-03-04')]]
for label, args, expected in cases[N - 1]:
    check(label, 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 fixture	Actual	Expected	Outcome
regression business-day-counting 1	`2026-03-10`	`2026-03-10`	Passed
regression business-day-counting 2	`2026-03-04`	`2026-03-05`	Failed
partial repair guard 2	`2026-05-01`	`2026-05-04`	Failed
control: plain t+2	`2026-03-04`	`2026-03-04`	Passed
control: over weekend	`2026-03-09`	`2026-03-09`	Passed
control: usd holiday t+1	`2026-03-04`	`2026-03-04`	Passed
control: usd holiday on spot	`2026-03-05`	`2026-03-05`	Passed

SHA-256 / c8d9d01979e8d6a7cd18b9bb0ffba018c32ca1c6cebbef8c268c8b367a46c9c6

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
from datetime import date, timedelta
N = 1
observations = []
def solve(trade, pair, holidays):
    d = date.fromisoformat(trade)
    base, quote = pair[:3], pair[3:]
    def good(x, ccys):
        return x.weekday() < 5 and all(x.isoformat() not in holidays.get(c, []) for c in ccys)
    lag = 1 if {base, quote} == {'USD', 'CAD'} else 2
    non_usd = [c for c in (base, quote) if c != 'USD']
    x, n = d, 0
    while n < lag:
        x += timedelta(days=1)
        if good(x, non_usd if n < lag - 1 else [base, quote]):
            n += 1
    return x.isoformat()
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
cases = [[('regression business-day-counting 1', ('2026-03-06', 'EURUSD', {}), '2026-03-10'),
  ('regression business-day-counting 2', ('2026-03-02', 'EURUSD', {'EUR': ['2026-03-03']}), '2026-03-05'),
  ('partial repair guard 2', ('2026-04-28', 'GBPJPY', {'JPY': ['2026-04-29', '2026-04-30']}), '2026-05-04'),
  ('control: plain t+2', ('2026-03-02', 'EURUSD', {}), '2026-03-04'),
  ('control: over weekend', ('2026-03-05', 'EURUSD', {}), '2026-03-09'),
  ('control: usd holiday t+1', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-03']}), '2026-03-04'),
  ('control: usd holiday on spot', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-04']}), '2026-03-05')],
 [('regression business-day-counting 1', ('2026-04-28', 'GBPJPY', {'JPY': ['2026-04-29', '2026-04-30']}), '2026-05-04'),
  ('regression business-day-counting 2',
   ('2026-03-30', 'EURGBP', {'EUR': ['2026-03-31', '2026-04-04'], 'CAD': ['2026-04-02'], 'GBP': ['2026-04-03']}),
   '2026-04-02'),
  ('partial repair guard 2',
   ('2026-10-09', 'GBPJPY',
    {'JPY': ['2026-10-11', '2026-10-12', '2026-10-13'],
     'EUR': ['2026-10-14'],
     'CAD': ['2026-10-10', '2026-10-11', '2026-10-12', '2026-10-13'],
     'GBP': ['2026-10-12', '2026-10-14']}),
   '2026-10-16'),
  ('control: usd holiday on spot', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-04']}), '2026-03-05'),
  ('control: cad t+1', ('2026-03-02', 'USDCAD', {}), '2026-03-03'),
  ('control: euro holiday t+1', ('2026-03-02', 'EURUSD', {'EUR': ['2026-03-03']}), '2026-03-05'),
  ('control: cross with cad', ('2026-03-02', 'EURCAD', {}), '2026-03-04')],
 [('regression business-day-counting 1',
   ('2026-10-09', 'GBPJPY',
    {'JPY': ['2026-10-11', '2026-10-12', '2026-10-13'],
     'EUR': ['2026-10-14'],
     'CAD': ['2026-10-10', '2026-10-11', '2026-10-12', '2026-10-13'],
     'GBP': ['2026-10-12', '2026-10-14']}),
   '2026-10-16'),
  ('regression business-day-counting 2',
   ('2026-08-14', 'GBPJPY',
    {'USD': [], 'JPY': ['2026-08-15', '2026-08-17', '2026-08-19'], 'EUR': ['2026-08-15', '2026-08-17']}),
   '2026-08-20'),
  ('partial repair guard 2',
   ('2026-07-22', 'EURUSD', {'EUR': ['2026-07-23', '2026-07-24', '2026-07-25'], 'CAD': ['2026-07-23', '2026-07-26']}),
   '2026-07-28'),
  ('control: cross with cad', ('2026-03-02', 'EURCAD', {}), '2026-03-04'),
  ('control: cad usd holiday', ('2026-03-06', 'CADUSD', {'USD': ['2026-03-09']}), '2026-03-10'),
  ('control: yen cross', ('2026-04-28', 'GBPJPY', {'JPY': ['2026-04-29', '2026-04-30']}), '2026-05-04'),
  ('control: plain t+2', ('2026-03-02', 'EURUSD', {}), '2026-03-04')],
 [('regression business-day-counting 1',
   ('2026-07-22', 'EURUSD', {'EUR': ['2026-07-23', '2026-07-24', '2026-07-25'], 'CAD': ['2026-07-23', '2026-07-26']}),
   '2026-07-28'),
  ('regression business-day-counting 2',
   ('2026-02-16', 'EURCAD',
    {'USD': ['2026-02-17', '2026-02-18', '2026-02-20'],
     'EUR': ['2026-02-17', '2026-02-21'],
     'CAD': [],
     'GBP': ['2026-02-17', '2026-02-20']}),
   '2026-02-19'),
  ('partial repair guard 2',
   ('2026-03-23', 'EURCAD',
    {'JPY': ['2026-03-27'], 'EUR': ['2026-03-25'], 'CAD': ['2026-03-24', '2026-03-26'], 'GBP': ['2026-03-25']}),
   '2026-03-30'),
  ('control: plain t+2', ('2026-03-02', 'EURUSD', {}), '2026-03-04'),
  ('control: over weekend', ('2026-03-05', 'EURUSD', {}), '2026-03-09'),
  ('control: usd holiday t+1', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-03']}), '2026-03-04'),
  ('control: usd holiday on spot', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-04']}), '2026-03-05')],
 [('regression business-day-counting 1',
   ('2026-03-23', 'EURCAD',
    {'JPY': ['2026-03-27'], 'EUR': ['2026-03-25'], 'CAD': ['2026-03-24', '2026-03-26'], 'GBP': ['2026-03-25']}),
   '2026-03-30'),
  ('regression business-day-counting 2',
   ('2026-08-28', 'EURCAD',
    {'USD': ['2026-08-30', '2026-08-31', '2026-09-01'],
     'EUR': ['2026-08-31', '2026-09-01'],
     'CAD': ['2026-08-29', '2026-08-31'],
     'GBP': ['2026-08-29', '2026-09-01']}),
   '2026-09-03'),
  ('partial repair guard 2',
   ('2026-03-19', 'EURCAD', {'USD': ['2026-03-21'], 'JPY': ['2026-03-20'], 'EUR': ['2026-03-20'], 'CAD': []}),
   '2026-03-24'),
  ('control: usd holiday on spot', ('2026-03-02', 'EURUSD', {'USD': ['2026-03-04']}), '2026-03-05'),
  ('control: cad t+1', ('2026-03-02', 'USDCAD', {}), '2026-03-03'),
  ('control: euro holiday t+1', ('2026-03-02', 'EURUSD', {'EUR': ['2026-03-03']}), '2026-03-05'),
  ('control: cross with cad', ('2026-03-02', 'EURCAD', {}), '2026-03-04')]]
for label, args, expected in cases[N - 1]:
    check(label, 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 fixture	Actual	Expected	Outcome
regression business-day-counting 1	`2026-03-10`	`2026-03-10`	Passed
regression business-day-counting 2	`2026-03-05`	`2026-03-05`	Passed
partial repair guard 2	`2026-05-04`	`2026-05-04`	Passed
control: plain t+2	`2026-03-04`	`2026-03-04`	Passed
control: over weekend	`2026-03-09`	`2026-03-09`	Passed
control: usd holiday t+1	`2026-03-04`	`2026-03-04`	Passed
control: usd holiday on spot	`2026-03-05`	`2026-03-05`	Passed

SHA-256 / 21bb5a302e89107aa1ba8a28a8ce9e3c2cd11e4866431b13fdcc11dbe729e2b4

Verification & scope

A deterministic, bounded teaching model with a stipulated toy contract; it makes no claim of conformance to any real regulation, standard, or institution's rules. 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 2026-09-29T14:47:02.133956+00:00.

Case digest / 15b7b4a938e9a6f53ad3d0194f00b20f1238fb0dce4089aab1eec26c06941cc7