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FA-57991 / Double-entry ledger accounting / Open access

Foreign currency period-end revaluation: rate orientation · case 01

Revalued balances move inversely to the exchange rate.

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

ROOT CAUSE

The quote is inverted, dividing by the home-per-foreign rate.

VERIFIED REPAIR

Multiply foreign units by num/den.

Unsuccessful approach: Truncating before the divmod fixes orientation but drops half-up rounding.

Case contract

x = {'bid': [num, den], 'ask': [num, den], 'accounts': [[name, 'asset'|'liability', monetary, foreign units, carried home cents]]}. Monetary assets are revalued at the bid rate and monetary liabilities at the ask rate: home = foreign * num / den rounded half-up per account. Non-monetary accounts keep their carried amount. Unrealized gain sums (new - carried) for assets and (carried - new) for liabilities. Return {'balances': [[name, home]], 'unrealized_gain'}.

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 to_home(amount, rate):
        num, den = rate
        q, r = divmod(amount * den, num)
        return q + (1 if 2 * r >= den else 0)
    gain = 0
    out = []
    for name, kind, monetary, foreign, carried in x['accounts']:
        if not monetary:
            out.append([name, carried])
            continue
        rate = x['bid'] if kind == 'asset' else x['ask']
        new = to_home(foreign, rate)
        delta = new - carried
        gain += delta if kind == 'asset' else -delta
        out.append([name, new])
    return {'balances': out, 'unrealized_gain': gain}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['regression: rate orientation', {'bid': [124, 100], 'ask': [125, 100], 'accounts': [['a0', 'liability', True, 7, 14], ['a1', 'liability', False, 7, 7], ['a2', 'liability', True, 5, 8]]}, {'balances': [['a0', 9], ['a1', 7], ['a2', 6]], 'unrealized_gain': 7}], ['control 1', {'bid': [1, 2], 'ask': [2, 2], 'accounts': [['a0', 'liability', True, 250, 500], ['a1', 'asset', False, 101, 101], ['a2', 'liability', True, 3, 500]]}, {'balances': [['a0', 250], ['a1', 101], ['a2', 3]], 'unrealized_gain': 747}], ['control 2', {'bid': [3, 4], 'ask': [4, 4], 'accounts': [['a0', 'liability', True, 1, 2], ['a1', 'liability', True, 1000, 500], ['a2', 'asset', False, 3, 6], ['a3', 'liability', True, 5, 500]]}, {'balances': [['a0', 1], ['a1', 1000], ['a2', 6], ['a3', 5]], 'unrealized_gain': -4}], ['control 3', {'bid': [5, 8], 'ask': [8, 8], 'accounts': [['a0', 'liability', False, 101, 500], ['a1', 'asset', False, 101, 101], ['a2', 'liability', True, 101, 104], ['a3', 'liability', True, 7, 14], ['a4', 'asset', False, 7, 500]]}, {'balances': [['a0', 500], ['a1', 101], ['a2', 101], ['a3', 7], ['a4', 500]], 'unrealized_gain': 10}], ['control 4', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'liability', False, 7, 10], ['a1', 'asset', True, 999, 999], ['a2', 'asset', False, 250, 500], ['a3', 'asset', False, 999, 500], ['a4', 'asset', True, 101, 500]]}, {'balances': [['a0', 10], ['a1', 999], ['a2', 500], ['a3', 500], ['a4', 101]], 'unrealized_gain': -399}], ['control 5', {'bid': [6, 4], 'ask': [8, 4], 'accounts': [['a0', 'asset', False, 5, 10], ['a1', 'asset', False, 7, 500]]}, {'balances': [['a0', 10], ['a1', 500]], 'unrealized_gain': 0}], ['control 6', {'bid': [5, 4], 'ask': [7, 4], 'accounts': [['a0', 'liability', False, 3, 6], ['a1', 'liability', False, 3, 6]]}, {'balances': [['a0', 6], ['a1', 6]], 'unrealized_gain': 0}]], [['regression: rate orientation', {'bid': [133, 100], 'ask': [135, 100], 'accounts': [['a0', 'liability', False, 3, 6], ['a1', 'asset', True, 1, 1], ['a2', 'liability', True, 7, 500], ['a3', 'liability', True, 3, 6]]}, {'balances': [['a0', 6], ['a1', 1], ['a2', 9], ['a3', 4]], 'unrealized_gain': 493}], ['regression: rate orientation, partial-repair probe', {'bid': [15, 8], 'ask': [17, 8], 'accounts': [['a0', 'liability', True, 999, 999], ['a1', 'liability', True, 101, 101], ['a2', 'asset', True, 7, 7], ['a3', 'liability', True, 101, 202]]}, {'balances': [['a0', 2123], ['a1', 215], ['a2', 13], ['a3', 215]], 'unrealized_gain': -1245}], ['control 1', {'bid': [119, 100], 'ask': [120, 100], 'accounts': [['a0', 'asset', False, 5, 500], ['a1', 'liability', False, 999, 500]]}, {'balances': [['a0', 500], ['a1', 500]], 'unrealized_gain': 0}], ['control 2', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', False, 5, 5], ['a1', 'asset', True, 1000, 500], ['a2', 'liability', False, 5, 5], ['a3', 'asset', True, 1, 2]]}, {'balances': [['a0', 5], ['a1', 1000], ['a2', 5], ['a3', 1]], 'unrealized_gain': 499}], ['control 3', {'bid': [99, 100], 'ask': [100, 100], 'accounts': [['a0', 'asset', True, 5, 5], ['a1', 'asset', False, 101, 202], ['a2', 'liability', True, 101, 500], ['a3', 'liability', True, 101, 500], ['a4', 'liability', False, 999, 1002]]}, {'balances': [['a0', 5], ['a1', 202], ['a2', 101], ['a3', 101], ['a4', 1002]], 'unrealized_gain': 798}], ['control 4', {'bid': [2, 4], 'ask': [4, 4], 'accounts': [['a0', 'liability', False, 999, 999], ['a1', 'liability', True, 3, 3], ['a2', 'liability', False, 250, 253]]}, {'balances': [['a0', 999], ['a1', 3], ['a2', 253]], 'unrealized_gain': 0}], ['control 5', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', False, 5, 8], ['a1', 'asset', True, 1000, 1000], ['a2', 'asset', True, 999, 1998], ['a3', 'liability', False, 999, 500]]}, {'balances': [['a0', 8], ['a1', 1000], ['a2', 999], ['a3', 500]], 'unrealized_gain': -999}]], [['regression: rate orientation', {'bid': [130, 100], 'ask': [132, 100], 'accounts': [['a0', 'asset', True, 1, 4], ['a1', 'asset', True, 7, 500]]}, {'balances': [['a0', 1], ['a1', 9]], 'unrealized_gain': -494}], ['regression: rate orientation, partial-repair probe', {'bid': [12, 10], 'ask': [14, 10], 'accounts': [['a0', 'asset', False, 1000, 2000], ['a1', 'liability', True, 1, 2], ['a2', 'liability', True, 3, 3], ['a3', 'liability', True, 999, 1002]]}, {'balances': [['a0', 2000], ['a1', 1], ['a2', 4], ['a3', 1399]], 'unrealized_gain': -397}], ['control 1', {'bid': [2, 2], 'ask': [3, 2], 'accounts': [['a0', 'asset', True, 3, 3], ['a1', 'asset', False, 5, 500], ['a2', 'asset', False, 999, 1998], ['a3', 'asset', True, 5, 5], ['a4', 'liability', False, 7, 14]]}, {'balances': [['a0', 3], ['a1', 500], ['a2', 1998], ['a3', 5], ['a4', 14]], 'unrealized_gain': 0}], ['control 2', {'bid': [1, 2], 'ask': [2, 2], 'accounts': [['a0', 'liability', True, 1, 2], ['a1', 'liability', True, 5, 500]]}, {'balances': [['a0', 1], ['a1', 5]], 'unrealized_gain': 496}], ['control 3', {'bid': [10, 10], 'ask': [11, 10], 'accounts': [['a0', 'asset', True, 999, 1998], ['a1', 'liability', False, 1000, 2000], ['a2', 'asset', True, 7, 10]]}, {'balances': [['a0', 999], ['a1', 2000], ['a2', 7]], 'unrealized_gain': -1002}], ['control 4', {'bid': [8, 8], 'ask': [9, 8], 'accounts': [['a0', 'liability', False, 1000, 500], ['a1', 'liability', False, 1, 500], ['a2', 'asset', False, 1, 1], ['a3', 'asset', True, 999, 1002]]}, {'balances': [['a0', 500], ['a1', 500], ['a2', 1], ['a3', 999]], 'unrealized_gain': -3}], ['control 5', {'bid': [105, 100], 'ask': [106, 100], 'accounts': [['a0', 'asset', False, 5, 10], ['a1', 'asset', False, 3, 6], ['a2', 'asset', False, 101, 101], ['a3', 'liability', False, 3, 6]]}, {'balances': [['a0', 10], ['a1', 6], ['a2', 101], ['a3', 6]], 'unrealized_gain': 0}]], [['regression: rate orientation', {'bid': [3, 2], 'ask': [4, 2], 'accounts': [['a0', 'liability', True, 999, 500], ['a1', 'liability', False, 3, 3], ['a2', 'liability', True, 5, 10]]}, {'balances': [['a0', 1998], ['a1', 3], ['a2', 10]], 'unrealized_gain': -1498}], ['regression: rate orientation, partial-repair probe', {'bid': [8, 4], 'ask': [9, 4], 'accounts': [['a0', 'asset', False, 250, 253], ['a1', 'liability', True, 5, 8], ['a2', 'asset', False, 5, 10], ['a3', 'liability', True, 5, 8], ['a4', 'liability', True, 999, 1998]]}, {'balances': [['a0', 253], ['a1', 11], ['a2', 10], ['a3', 11], ['a4', 2248]], 'unrealized_gain': -256}], ['control 1', {'bid': [8, 8], 'ask': [9, 8], 'accounts': [['a0', 'asset', False, 101, 101], ['a1', 'asset', False, 5, 500]]}, {'balances': [['a0', 101], ['a1', 500]], 'unrealized_gain': 0}], ['control 2', {'bid': [9, 8], 'ask': [11, 8], 'accounts': [['a0', 'asset', False, 1000, 2000], ['a1', 'asset', True, 1, 2]]}, {'balances': [['a0', 2000], ['a1', 1]], 'unrealized_gain': -1}], ['control 3', {'bid': [7, 10], 'ask': [10, 10], 'accounts': [['a0', 'asset', False, 5, 8], ['a1', 'asset', False, 250, 253]]}, {'balances': [['a0', 8], ['a1', 253]], 'unrealized_gain': 0}], ['control 4', {'bid': [10, 10], 'ask': [11, 10], 'accounts': [['a0', 'asset', True, 3, 3], ['a1', 'asset', True, 250, 500]]}, {'balances': [['a0', 3], ['a1', 250]], 'unrealized_gain': -250}], ['control 5', {'bid': [84, 100], 'ask': [87, 100], 'accounts': [['a0', 'asset', False, 1, 1], ['a1', 'liability', False, 1, 2], ['a2', 'asset', False, 999, 1998]]}, {'balances': [['a0', 1], ['a1', 2], ['a2', 1998]], 'unrealized_gain': 0}]], [['regression: rate orientation', {'bid': [158, 100], 'ask': [159, 100], 'accounts': [['a0', 'liability', True, 1, 1], ['a1', 'asset', False, 999, 1002], ['a2', 'liability', True, 1, 2], ['a3', 'liability', False, 1000, 1003]]}, {'balances': [['a0', 2], ['a1', 1002], ['a2', 2], ['a3', 1003]], 'unrealized_gain': -1}], ['control 1', {'bid': [9, 10], 'ask': [10, 10], 'accounts': [['a0', 'liability', False, 101, 500], ['a1', 'asset', False, 7, 14], ['a2', 'liability', True, 7, 10], ['a3', 'asset', False, 101, 101]]}, {'balances': [['a0', 500], ['a1', 14], ['a2', 7], ['a3', 101]], 'unrealized_gain': 3}], ['control 2', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', False, 7, 7], ['a1', 'liability', False, 101, 500]]}, {'balances': [['a0', 7], ['a1', 500]], 'unrealized_gain': 0}], ['control 3', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', True, 7, 10], ['a1', 'liability', False, 101, 202]]}, {'balances': [['a0', 7], ['a1', 202]], 'unrealized_gain': -3}], ['control 4', {'bid': [2, 2], 'ask': [3, 2], 'accounts': [['a0', 'asset', True, 1000, 2000], ['a1', 'asset', True, 7, 500]]}, {'balances': [['a0', 1000], ['a1', 7]], 'unrealized_gain': -1493}], ['control 5', {'bid': [102, 100], 'ask': [103, 100], 'accounts': [['a0', 'liability', False, 999, 1002], ['a1', 'liability', True, 3, 3]]}, {'balances': [['a0', 1002], ['a1', 3]], 'unrealized_gain': 0}], ['control 6', {'bid': [15, 10], 'ask': [18, 10], 'accounts': [['a0', 'asset', False, 999, 500], ['a1', 'asset', False, 250, 500]]}, {'balances': [['a0', 500], ['a1', 500]], 'unrealized_gain': 0}]]]
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: rate orientation{'balances': [['a0', 6], ['a1', 7], ['a2', 4]], 'unrealized_gain': 12}{'balances': [['a0', 9], ['a1', 7], ['a2', 6]], 'unrealized_gain': 7}Failed
control 1{'balances': [['a0', 250], ['a1', 101], ['a2', 3]], 'unrealized_gain': 747}{'balances': [['a0', 250], ['a1', 101], ['a2', 3]], 'unrealized_gain': 747}Passed
control 2{'balances': [['a0', 1], ['a1', 1000], ['a2', 6], ['a3', 5]], 'unrealized_gain': -4}{'balances': [['a0', 1], ['a1', 1000], ['a2', 6], ['a3', 5]], 'unrealized_gain': -4}Passed
control 3{'balances': [['a0', 500], ['a1', 101], ['a2', 101], ['a3', 7], ['a4', 500]], 'unrealized_gain': 10}{'balances': [['a0', 500], ['a1', 101], ['a2', 101], ['a3', 7], ['a4', 500]], 'unrealized_gain': 10}Passed
control 4{'balances': [['a0', 10], ['a1', 999], ['a2', 500], ['a3', 500], ['a4', 101]], 'unrealized_gain': -399}{'balances': [['a0', 10], ['a1', 999], ['a2', 500], ['a3', 500], ['a4', 101]], 'unrealized_gain': -399}Passed
control 5{'balances': [['a0', 10], ['a1', 500]], 'unrealized_gain': 0}{'balances': [['a0', 10], ['a1', 500]], 'unrealized_gain': 0}Passed
control 6{'balances': [['a0', 6], ['a1', 6]], 'unrealized_gain': 0}{'balances': [['a0', 6], ['a1', 6]], 'unrealized_gain': 0}Passed

SHA-256 / 0b17ff2c767fbf5d96fc6ad9b00a5d7f5090c0160f9cfa1734c445a8b1bc2b9d

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(x):
    def to_home(amount, rate):
        num, den = rate
        q, r = divmod(amount * num // den, 1)
        return q + (1 if 2 * r >= den else 0)
    gain = 0
    out = []
    for name, kind, monetary, foreign, carried in x['accounts']:
        if not monetary:
            out.append([name, carried])
            continue
        rate = x['bid'] if kind == 'asset' else x['ask']
        new = to_home(foreign, rate)
        delta = new - carried
        gain += delta if kind == 'asset' else -delta
        out.append([name, new])
    return {'balances': out, 'unrealized_gain': gain}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['regression: rate orientation', {'bid': [124, 100], 'ask': [125, 100], 'accounts': [['a0', 'liability', True, 7, 14], ['a1', 'liability', False, 7, 7], ['a2', 'liability', True, 5, 8]]}, {'balances': [['a0', 9], ['a1', 7], ['a2', 6]], 'unrealized_gain': 7}], ['control 1', {'bid': [1, 2], 'ask': [2, 2], 'accounts': [['a0', 'liability', True, 250, 500], ['a1', 'asset', False, 101, 101], ['a2', 'liability', True, 3, 500]]}, {'balances': [['a0', 250], ['a1', 101], ['a2', 3]], 'unrealized_gain': 747}], ['control 2', {'bid': [3, 4], 'ask': [4, 4], 'accounts': [['a0', 'liability', True, 1, 2], ['a1', 'liability', True, 1000, 500], ['a2', 'asset', False, 3, 6], ['a3', 'liability', True, 5, 500]]}, {'balances': [['a0', 1], ['a1', 1000], ['a2', 6], ['a3', 5]], 'unrealized_gain': -4}], ['control 3', {'bid': [5, 8], 'ask': [8, 8], 'accounts': [['a0', 'liability', False, 101, 500], ['a1', 'asset', False, 101, 101], ['a2', 'liability', True, 101, 104], ['a3', 'liability', True, 7, 14], ['a4', 'asset', False, 7, 500]]}, {'balances': [['a0', 500], ['a1', 101], ['a2', 101], ['a3', 7], ['a4', 500]], 'unrealized_gain': 10}], ['control 4', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'liability', False, 7, 10], ['a1', 'asset', True, 999, 999], ['a2', 'asset', False, 250, 500], ['a3', 'asset', False, 999, 500], ['a4', 'asset', True, 101, 500]]}, {'balances': [['a0', 10], ['a1', 999], ['a2', 500], ['a3', 500], ['a4', 101]], 'unrealized_gain': -399}], ['control 5', {'bid': [6, 4], 'ask': [8, 4], 'accounts': [['a0', 'asset', False, 5, 10], ['a1', 'asset', False, 7, 500]]}, {'balances': [['a0', 10], ['a1', 500]], 'unrealized_gain': 0}], ['control 6', {'bid': [5, 4], 'ask': [7, 4], 'accounts': [['a0', 'liability', False, 3, 6], ['a1', 'liability', False, 3, 6]]}, {'balances': [['a0', 6], ['a1', 6]], 'unrealized_gain': 0}]], [['regression: rate orientation', {'bid': [133, 100], 'ask': [135, 100], 'accounts': [['a0', 'liability', False, 3, 6], ['a1', 'asset', True, 1, 1], ['a2', 'liability', True, 7, 500], ['a3', 'liability', True, 3, 6]]}, {'balances': [['a0', 6], ['a1', 1], ['a2', 9], ['a3', 4]], 'unrealized_gain': 493}], ['regression: rate orientation, partial-repair probe', {'bid': [15, 8], 'ask': [17, 8], 'accounts': [['a0', 'liability', True, 999, 999], ['a1', 'liability', True, 101, 101], ['a2', 'asset', True, 7, 7], ['a3', 'liability', True, 101, 202]]}, {'balances': [['a0', 2123], ['a1', 215], ['a2', 13], ['a3', 215]], 'unrealized_gain': -1245}], ['control 1', {'bid': [119, 100], 'ask': [120, 100], 'accounts': [['a0', 'asset', False, 5, 500], ['a1', 'liability', False, 999, 500]]}, {'balances': [['a0', 500], ['a1', 500]], 'unrealized_gain': 0}], ['control 2', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', False, 5, 5], ['a1', 'asset', True, 1000, 500], ['a2', 'liability', False, 5, 5], ['a3', 'asset', True, 1, 2]]}, {'balances': [['a0', 5], ['a1', 1000], ['a2', 5], ['a3', 1]], 'unrealized_gain': 499}], ['control 3', {'bid': [99, 100], 'ask': [100, 100], 'accounts': [['a0', 'asset', True, 5, 5], ['a1', 'asset', False, 101, 202], ['a2', 'liability', True, 101, 500], ['a3', 'liability', True, 101, 500], ['a4', 'liability', False, 999, 1002]]}, {'balances': [['a0', 5], ['a1', 202], ['a2', 101], ['a3', 101], ['a4', 1002]], 'unrealized_gain': 798}], ['control 4', {'bid': [2, 4], 'ask': [4, 4], 'accounts': [['a0', 'liability', False, 999, 999], ['a1', 'liability', True, 3, 3], ['a2', 'liability', False, 250, 253]]}, {'balances': [['a0', 999], ['a1', 3], ['a2', 253]], 'unrealized_gain': 0}], ['control 5', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', False, 5, 8], ['a1', 'asset', True, 1000, 1000], ['a2', 'asset', True, 999, 1998], ['a3', 'liability', False, 999, 500]]}, {'balances': [['a0', 8], ['a1', 1000], ['a2', 999], ['a3', 500]], 'unrealized_gain': -999}]], [['regression: rate orientation', {'bid': [130, 100], 'ask': [132, 100], 'accounts': [['a0', 'asset', True, 1, 4], ['a1', 'asset', True, 7, 500]]}, {'balances': [['a0', 1], ['a1', 9]], 'unrealized_gain': -494}], ['regression: rate orientation, partial-repair probe', {'bid': [12, 10], 'ask': [14, 10], 'accounts': [['a0', 'asset', False, 1000, 2000], ['a1', 'liability', True, 1, 2], ['a2', 'liability', True, 3, 3], ['a3', 'liability', True, 999, 1002]]}, {'balances': [['a0', 2000], ['a1', 1], ['a2', 4], ['a3', 1399]], 'unrealized_gain': -397}], ['control 1', {'bid': [2, 2], 'ask': [3, 2], 'accounts': [['a0', 'asset', True, 3, 3], ['a1', 'asset', False, 5, 500], ['a2', 'asset', False, 999, 1998], ['a3', 'asset', True, 5, 5], ['a4', 'liability', False, 7, 14]]}, {'balances': [['a0', 3], ['a1', 500], ['a2', 1998], ['a3', 5], ['a4', 14]], 'unrealized_gain': 0}], ['control 2', {'bid': [1, 2], 'ask': [2, 2], 'accounts': [['a0', 'liability', True, 1, 2], ['a1', 'liability', True, 5, 500]]}, {'balances': [['a0', 1], ['a1', 5]], 'unrealized_gain': 496}], ['control 3', {'bid': [10, 10], 'ask': [11, 10], 'accounts': [['a0', 'asset', True, 999, 1998], ['a1', 'liability', False, 1000, 2000], ['a2', 'asset', True, 7, 10]]}, {'balances': [['a0', 999], ['a1', 2000], ['a2', 7]], 'unrealized_gain': -1002}], ['control 4', {'bid': [8, 8], 'ask': [9, 8], 'accounts': [['a0', 'liability', False, 1000, 500], ['a1', 'liability', False, 1, 500], ['a2', 'asset', False, 1, 1], ['a3', 'asset', True, 999, 1002]]}, {'balances': [['a0', 500], ['a1', 500], ['a2', 1], ['a3', 999]], 'unrealized_gain': -3}], ['control 5', {'bid': [105, 100], 'ask': [106, 100], 'accounts': [['a0', 'asset', False, 5, 10], ['a1', 'asset', False, 3, 6], ['a2', 'asset', False, 101, 101], ['a3', 'liability', False, 3, 6]]}, {'balances': [['a0', 10], ['a1', 6], ['a2', 101], ['a3', 6]], 'unrealized_gain': 0}]], [['regression: rate orientation', {'bid': [3, 2], 'ask': [4, 2], 'accounts': [['a0', 'liability', True, 999, 500], ['a1', 'liability', False, 3, 3], ['a2', 'liability', True, 5, 10]]}, {'balances': [['a0', 1998], ['a1', 3], ['a2', 10]], 'unrealized_gain': -1498}], ['regression: rate orientation, partial-repair probe', {'bid': [8, 4], 'ask': [9, 4], 'accounts': [['a0', 'asset', False, 250, 253], ['a1', 'liability', True, 5, 8], ['a2', 'asset', False, 5, 10], ['a3', 'liability', True, 5, 8], ['a4', 'liability', True, 999, 1998]]}, {'balances': [['a0', 253], ['a1', 11], ['a2', 10], ['a3', 11], ['a4', 2248]], 'unrealized_gain': -256}], ['control 1', {'bid': [8, 8], 'ask': [9, 8], 'accounts': [['a0', 'asset', False, 101, 101], ['a1', 'asset', False, 5, 500]]}, {'balances': [['a0', 101], ['a1', 500]], 'unrealized_gain': 0}], ['control 2', {'bid': [9, 8], 'ask': [11, 8], 'accounts': [['a0', 'asset', False, 1000, 2000], ['a1', 'asset', True, 1, 2]]}, {'balances': [['a0', 2000], ['a1', 1]], 'unrealized_gain': -1}], ['control 3', {'bid': [7, 10], 'ask': [10, 10], 'accounts': [['a0', 'asset', False, 5, 8], ['a1', 'asset', False, 250, 253]]}, {'balances': [['a0', 8], ['a1', 253]], 'unrealized_gain': 0}], ['control 4', {'bid': [10, 10], 'ask': [11, 10], 'accounts': [['a0', 'asset', True, 3, 3], ['a1', 'asset', True, 250, 500]]}, {'balances': [['a0', 3], ['a1', 250]], 'unrealized_gain': -250}], ['control 5', {'bid': [84, 100], 'ask': [87, 100], 'accounts': [['a0', 'asset', False, 1, 1], ['a1', 'liability', False, 1, 2], ['a2', 'asset', False, 999, 1998]]}, {'balances': [['a0', 1], ['a1', 2], ['a2', 1998]], 'unrealized_gain': 0}]], [['regression: rate orientation', {'bid': [158, 100], 'ask': [159, 100], 'accounts': [['a0', 'liability', True, 1, 1], ['a1', 'asset', False, 999, 1002], ['a2', 'liability', True, 1, 2], ['a3', 'liability', False, 1000, 1003]]}, {'balances': [['a0', 2], ['a1', 1002], ['a2', 2], ['a3', 1003]], 'unrealized_gain': -1}], ['control 1', {'bid': [9, 10], 'ask': [10, 10], 'accounts': [['a0', 'liability', False, 101, 500], ['a1', 'asset', False, 7, 14], ['a2', 'liability', True, 7, 10], ['a3', 'asset', False, 101, 101]]}, {'balances': [['a0', 500], ['a1', 14], ['a2', 7], ['a3', 101]], 'unrealized_gain': 3}], ['control 2', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', False, 7, 7], ['a1', 'liability', False, 101, 500]]}, {'balances': [['a0', 7], ['a1', 500]], 'unrealized_gain': 0}], ['control 3', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', True, 7, 10], ['a1', 'liability', False, 101, 202]]}, {'balances': [['a0', 7], ['a1', 202]], 'unrealized_gain': -3}], ['control 4', {'bid': [2, 2], 'ask': [3, 2], 'accounts': [['a0', 'asset', True, 1000, 2000], ['a1', 'asset', True, 7, 500]]}, {'balances': [['a0', 1000], ['a1', 7]], 'unrealized_gain': -1493}], ['control 5', {'bid': [102, 100], 'ask': [103, 100], 'accounts': [['a0', 'liability', False, 999, 1002], ['a1', 'liability', True, 3, 3]]}, {'balances': [['a0', 1002], ['a1', 3]], 'unrealized_gain': 0}], ['control 6', {'bid': [15, 10], 'ask': [18, 10], 'accounts': [['a0', 'asset', False, 999, 500], ['a1', 'asset', False, 250, 500]]}, {'balances': [['a0', 500], ['a1', 500]], 'unrealized_gain': 0}]]]
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: rate orientation{'balances': [['a0', 8], ['a1', 7], ['a2', 6]], 'unrealized_gain': 8}{'balances': [['a0', 9], ['a1', 7], ['a2', 6]], 'unrealized_gain': 7}Failed
control 1{'balances': [['a0', 250], ['a1', 101], ['a2', 3]], 'unrealized_gain': 747}{'balances': [['a0', 250], ['a1', 101], ['a2', 3]], 'unrealized_gain': 747}Passed
control 2{'balances': [['a0', 1], ['a1', 1000], ['a2', 6], ['a3', 5]], 'unrealized_gain': -4}{'balances': [['a0', 1], ['a1', 1000], ['a2', 6], ['a3', 5]], 'unrealized_gain': -4}Passed
control 3{'balances': [['a0', 500], ['a1', 101], ['a2', 101], ['a3', 7], ['a4', 500]], 'unrealized_gain': 10}{'balances': [['a0', 500], ['a1', 101], ['a2', 101], ['a3', 7], ['a4', 500]], 'unrealized_gain': 10}Passed
control 4{'balances': [['a0', 10], ['a1', 999], ['a2', 500], ['a3', 500], ['a4', 101]], 'unrealized_gain': -399}{'balances': [['a0', 10], ['a1', 999], ['a2', 500], ['a3', 500], ['a4', 101]], 'unrealized_gain': -399}Passed
control 5{'balances': [['a0', 10], ['a1', 500]], 'unrealized_gain': 0}{'balances': [['a0', 10], ['a1', 500]], 'unrealized_gain': 0}Passed
control 6{'balances': [['a0', 6], ['a1', 6]], 'unrealized_gain': 0}{'balances': [['a0', 6], ['a1', 6]], 'unrealized_gain': 0}Passed

SHA-256 / 8aa8c85735b32170aa428436e2c51b13c3c593637b6e3fa79897a4923bb95b29

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    def to_home(amount, rate):
        num, den = rate
        q, r = divmod(amount * num, den)
        return q + (1 if 2 * r >= den else 0)
    gain = 0
    out = []
    for name, kind, monetary, foreign, carried in x['accounts']:
        if not monetary:
            out.append([name, carried])
            continue
        rate = x['bid'] if kind == 'asset' else x['ask']
        new = to_home(foreign, rate)
        delta = new - carried
        gain += delta if kind == 'asset' else -delta
        out.append([name, new])
    return {'balances': out, 'unrealized_gain': gain}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['regression: rate orientation', {'bid': [124, 100], 'ask': [125, 100], 'accounts': [['a0', 'liability', True, 7, 14], ['a1', 'liability', False, 7, 7], ['a2', 'liability', True, 5, 8]]}, {'balances': [['a0', 9], ['a1', 7], ['a2', 6]], 'unrealized_gain': 7}], ['control 1', {'bid': [1, 2], 'ask': [2, 2], 'accounts': [['a0', 'liability', True, 250, 500], ['a1', 'asset', False, 101, 101], ['a2', 'liability', True, 3, 500]]}, {'balances': [['a0', 250], ['a1', 101], ['a2', 3]], 'unrealized_gain': 747}], ['control 2', {'bid': [3, 4], 'ask': [4, 4], 'accounts': [['a0', 'liability', True, 1, 2], ['a1', 'liability', True, 1000, 500], ['a2', 'asset', False, 3, 6], ['a3', 'liability', True, 5, 500]]}, {'balances': [['a0', 1], ['a1', 1000], ['a2', 6], ['a3', 5]], 'unrealized_gain': -4}], ['control 3', {'bid': [5, 8], 'ask': [8, 8], 'accounts': [['a0', 'liability', False, 101, 500], ['a1', 'asset', False, 101, 101], ['a2', 'liability', True, 101, 104], ['a3', 'liability', True, 7, 14], ['a4', 'asset', False, 7, 500]]}, {'balances': [['a0', 500], ['a1', 101], ['a2', 101], ['a3', 7], ['a4', 500]], 'unrealized_gain': 10}], ['control 4', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'liability', False, 7, 10], ['a1', 'asset', True, 999, 999], ['a2', 'asset', False, 250, 500], ['a3', 'asset', False, 999, 500], ['a4', 'asset', True, 101, 500]]}, {'balances': [['a0', 10], ['a1', 999], ['a2', 500], ['a3', 500], ['a4', 101]], 'unrealized_gain': -399}], ['control 5', {'bid': [6, 4], 'ask': [8, 4], 'accounts': [['a0', 'asset', False, 5, 10], ['a1', 'asset', False, 7, 500]]}, {'balances': [['a0', 10], ['a1', 500]], 'unrealized_gain': 0}], ['control 6', {'bid': [5, 4], 'ask': [7, 4], 'accounts': [['a0', 'liability', False, 3, 6], ['a1', 'liability', False, 3, 6]]}, {'balances': [['a0', 6], ['a1', 6]], 'unrealized_gain': 0}]], [['regression: rate orientation', {'bid': [133, 100], 'ask': [135, 100], 'accounts': [['a0', 'liability', False, 3, 6], ['a1', 'asset', True, 1, 1], ['a2', 'liability', True, 7, 500], ['a3', 'liability', True, 3, 6]]}, {'balances': [['a0', 6], ['a1', 1], ['a2', 9], ['a3', 4]], 'unrealized_gain': 493}], ['regression: rate orientation, partial-repair probe', {'bid': [15, 8], 'ask': [17, 8], 'accounts': [['a0', 'liability', True, 999, 999], ['a1', 'liability', True, 101, 101], ['a2', 'asset', True, 7, 7], ['a3', 'liability', True, 101, 202]]}, {'balances': [['a0', 2123], ['a1', 215], ['a2', 13], ['a3', 215]], 'unrealized_gain': -1245}], ['control 1', {'bid': [119, 100], 'ask': [120, 100], 'accounts': [['a0', 'asset', False, 5, 500], ['a1', 'liability', False, 999, 500]]}, {'balances': [['a0', 500], ['a1', 500]], 'unrealized_gain': 0}], ['control 2', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', False, 5, 5], ['a1', 'asset', True, 1000, 500], ['a2', 'liability', False, 5, 5], ['a3', 'asset', True, 1, 2]]}, {'balances': [['a0', 5], ['a1', 1000], ['a2', 5], ['a3', 1]], 'unrealized_gain': 499}], ['control 3', {'bid': [99, 100], 'ask': [100, 100], 'accounts': [['a0', 'asset', True, 5, 5], ['a1', 'asset', False, 101, 202], ['a2', 'liability', True, 101, 500], ['a3', 'liability', True, 101, 500], ['a4', 'liability', False, 999, 1002]]}, {'balances': [['a0', 5], ['a1', 202], ['a2', 101], ['a3', 101], ['a4', 1002]], 'unrealized_gain': 798}], ['control 4', {'bid': [2, 4], 'ask': [4, 4], 'accounts': [['a0', 'liability', False, 999, 999], ['a1', 'liability', True, 3, 3], ['a2', 'liability', False, 250, 253]]}, {'balances': [['a0', 999], ['a1', 3], ['a2', 253]], 'unrealized_gain': 0}], ['control 5', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', False, 5, 8], ['a1', 'asset', True, 1000, 1000], ['a2', 'asset', True, 999, 1998], ['a3', 'liability', False, 999, 500]]}, {'balances': [['a0', 8], ['a1', 1000], ['a2', 999], ['a3', 500]], 'unrealized_gain': -999}]], [['regression: rate orientation', {'bid': [130, 100], 'ask': [132, 100], 'accounts': [['a0', 'asset', True, 1, 4], ['a1', 'asset', True, 7, 500]]}, {'balances': [['a0', 1], ['a1', 9]], 'unrealized_gain': -494}], ['regression: rate orientation, partial-repair probe', {'bid': [12, 10], 'ask': [14, 10], 'accounts': [['a0', 'asset', False, 1000, 2000], ['a1', 'liability', True, 1, 2], ['a2', 'liability', True, 3, 3], ['a3', 'liability', True, 999, 1002]]}, {'balances': [['a0', 2000], ['a1', 1], ['a2', 4], ['a3', 1399]], 'unrealized_gain': -397}], ['control 1', {'bid': [2, 2], 'ask': [3, 2], 'accounts': [['a0', 'asset', True, 3, 3], ['a1', 'asset', False, 5, 500], ['a2', 'asset', False, 999, 1998], ['a3', 'asset', True, 5, 5], ['a4', 'liability', False, 7, 14]]}, {'balances': [['a0', 3], ['a1', 500], ['a2', 1998], ['a3', 5], ['a4', 14]], 'unrealized_gain': 0}], ['control 2', {'bid': [1, 2], 'ask': [2, 2], 'accounts': [['a0', 'liability', True, 1, 2], ['a1', 'liability', True, 5, 500]]}, {'balances': [['a0', 1], ['a1', 5]], 'unrealized_gain': 496}], ['control 3', {'bid': [10, 10], 'ask': [11, 10], 'accounts': [['a0', 'asset', True, 999, 1998], ['a1', 'liability', False, 1000, 2000], ['a2', 'asset', True, 7, 10]]}, {'balances': [['a0', 999], ['a1', 2000], ['a2', 7]], 'unrealized_gain': -1002}], ['control 4', {'bid': [8, 8], 'ask': [9, 8], 'accounts': [['a0', 'liability', False, 1000, 500], ['a1', 'liability', False, 1, 500], ['a2', 'asset', False, 1, 1], ['a3', 'asset', True, 999, 1002]]}, {'balances': [['a0', 500], ['a1', 500], ['a2', 1], ['a3', 999]], 'unrealized_gain': -3}], ['control 5', {'bid': [105, 100], 'ask': [106, 100], 'accounts': [['a0', 'asset', False, 5, 10], ['a1', 'asset', False, 3, 6], ['a2', 'asset', False, 101, 101], ['a3', 'liability', False, 3, 6]]}, {'balances': [['a0', 10], ['a1', 6], ['a2', 101], ['a3', 6]], 'unrealized_gain': 0}]], [['regression: rate orientation', {'bid': [3, 2], 'ask': [4, 2], 'accounts': [['a0', 'liability', True, 999, 500], ['a1', 'liability', False, 3, 3], ['a2', 'liability', True, 5, 10]]}, {'balances': [['a0', 1998], ['a1', 3], ['a2', 10]], 'unrealized_gain': -1498}], ['regression: rate orientation, partial-repair probe', {'bid': [8, 4], 'ask': [9, 4], 'accounts': [['a0', 'asset', False, 250, 253], ['a1', 'liability', True, 5, 8], ['a2', 'asset', False, 5, 10], ['a3', 'liability', True, 5, 8], ['a4', 'liability', True, 999, 1998]]}, {'balances': [['a0', 253], ['a1', 11], ['a2', 10], ['a3', 11], ['a4', 2248]], 'unrealized_gain': -256}], ['control 1', {'bid': [8, 8], 'ask': [9, 8], 'accounts': [['a0', 'asset', False, 101, 101], ['a1', 'asset', False, 5, 500]]}, {'balances': [['a0', 101], ['a1', 500]], 'unrealized_gain': 0}], ['control 2', {'bid': [9, 8], 'ask': [11, 8], 'accounts': [['a0', 'asset', False, 1000, 2000], ['a1', 'asset', True, 1, 2]]}, {'balances': [['a0', 2000], ['a1', 1]], 'unrealized_gain': -1}], ['control 3', {'bid': [7, 10], 'ask': [10, 10], 'accounts': [['a0', 'asset', False, 5, 8], ['a1', 'asset', False, 250, 253]]}, {'balances': [['a0', 8], ['a1', 253]], 'unrealized_gain': 0}], ['control 4', {'bid': [10, 10], 'ask': [11, 10], 'accounts': [['a0', 'asset', True, 3, 3], ['a1', 'asset', True, 250, 500]]}, {'balances': [['a0', 3], ['a1', 250]], 'unrealized_gain': -250}], ['control 5', {'bid': [84, 100], 'ask': [87, 100], 'accounts': [['a0', 'asset', False, 1, 1], ['a1', 'liability', False, 1, 2], ['a2', 'asset', False, 999, 1998]]}, {'balances': [['a0', 1], ['a1', 2], ['a2', 1998]], 'unrealized_gain': 0}]], [['regression: rate orientation', {'bid': [158, 100], 'ask': [159, 100], 'accounts': [['a0', 'liability', True, 1, 1], ['a1', 'asset', False, 999, 1002], ['a2', 'liability', True, 1, 2], ['a3', 'liability', False, 1000, 1003]]}, {'balances': [['a0', 2], ['a1', 1002], ['a2', 2], ['a3', 1003]], 'unrealized_gain': -1}], ['control 1', {'bid': [9, 10], 'ask': [10, 10], 'accounts': [['a0', 'liability', False, 101, 500], ['a1', 'asset', False, 7, 14], ['a2', 'liability', True, 7, 10], ['a3', 'asset', False, 101, 101]]}, {'balances': [['a0', 500], ['a1', 14], ['a2', 7], ['a3', 101]], 'unrealized_gain': 3}], ['control 2', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', False, 7, 7], ['a1', 'liability', False, 101, 500]]}, {'balances': [['a0', 7], ['a1', 500]], 'unrealized_gain': 0}], ['control 3', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', True, 7, 10], ['a1', 'liability', False, 101, 202]]}, {'balances': [['a0', 7], ['a1', 202]], 'unrealized_gain': -3}], ['control 4', {'bid': [2, 2], 'ask': [3, 2], 'accounts': [['a0', 'asset', True, 1000, 2000], ['a1', 'asset', True, 7, 500]]}, {'balances': [['a0', 1000], ['a1', 7]], 'unrealized_gain': -1493}], ['control 5', {'bid': [102, 100], 'ask': [103, 100], 'accounts': [['a0', 'liability', False, 999, 1002], ['a1', 'liability', True, 3, 3]]}, {'balances': [['a0', 1002], ['a1', 3]], 'unrealized_gain': 0}], ['control 6', {'bid': [15, 10], 'ask': [18, 10], 'accounts': [['a0', 'asset', False, 999, 500], ['a1', 'asset', False, 250, 500]]}, {'balances': [['a0', 500], ['a1', 500]], 'unrealized_gain': 0}]]]
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: rate orientation{'balances': [['a0', 9], ['a1', 7], ['a2', 6]], 'unrealized_gain': 7}{'balances': [['a0', 9], ['a1', 7], ['a2', 6]], 'unrealized_gain': 7}Passed
control 1{'balances': [['a0', 250], ['a1', 101], ['a2', 3]], 'unrealized_gain': 747}{'balances': [['a0', 250], ['a1', 101], ['a2', 3]], 'unrealized_gain': 747}Passed
control 2{'balances': [['a0', 1], ['a1', 1000], ['a2', 6], ['a3', 5]], 'unrealized_gain': -4}{'balances': [['a0', 1], ['a1', 1000], ['a2', 6], ['a3', 5]], 'unrealized_gain': -4}Passed
control 3{'balances': [['a0', 500], ['a1', 101], ['a2', 101], ['a3', 7], ['a4', 500]], 'unrealized_gain': 10}{'balances': [['a0', 500], ['a1', 101], ['a2', 101], ['a3', 7], ['a4', 500]], 'unrealized_gain': 10}Passed
control 4{'balances': [['a0', 10], ['a1', 999], ['a2', 500], ['a3', 500], ['a4', 101]], 'unrealized_gain': -399}{'balances': [['a0', 10], ['a1', 999], ['a2', 500], ['a3', 500], ['a4', 101]], 'unrealized_gain': -399}Passed
control 5{'balances': [['a0', 10], ['a1', 500]], 'unrealized_gain': 0}{'balances': [['a0', 10], ['a1', 500]], 'unrealized_gain': 0}Passed
control 6{'balances': [['a0', 6], ['a1', 6]], 'unrealized_gain': 0}{'balances': [['a0', 6], ['a1', 6]], 'unrealized_gain': 0}Passed

SHA-256 / df9d845a0bb8fa132893fa8efac381596f575e148ee48968352bcfa28b7f37be

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 2026-09-29T14:46:22.468751+00:00.

Case digest / 9877059c65639dda7cf012db8e25d9688f5f33880e4c5c26b932538ff28c85a8