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FA-57996 / Double-entry ledger accounting / Open access

Foreign currency period-end revaluation: delta baseline · case 01

Unrealized gains equal the full converted balance minus foreign units.

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

ROOT CAUSE

The revaluation delta compares against foreign units instead of the carried home amount.

THE FAILURE

The revaluation delta compares against foreign units instead of the carried home amount.

Unsuccessful approach: Converting the carried amount again treats a home figure as foreign units.

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 * 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 - foreign
        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: delta baseline', {'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': [8, 4], 'ask': [11, 4], 'accounts': [['a0', 'asset', True, 1000, 1000], ['a1', 'asset', False, 7, 7], ['a2', 'asset', True, 250, 250], ['a3', 'liability', False, 5, 8], ['a4', 'liability', False, 1000, 1000]]}, {'balances': [['a0', 2000], ['a1', 7], ['a2', 500], ['a3', 8], ['a4', 1000]], 'unrealized_gain': 1250}], ['control 2', {'bid': [5, 8], 'ask': [6, 8], 'accounts': [['a0', 'asset', True, 101, 101], ['a1', 'asset', False, 1, 4]]}, {'balances': [['a0', 63], ['a1', 4]], 'unrealized_gain': -38}], ['control 3', {'bid': [17, 10], 'ask': [20, 10], 'accounts': [['a0', 'asset', False, 101, 104], ['a1', 'liability', True, 5, 5], ['a2', 'asset', True, 7, 500], ['a3', 'liability', True, 7, 500]]}, {'balances': [['a0', 104], ['a1', 10], ['a2', 12], ['a3', 14]], 'unrealized_gain': -7}], ['control 4', {'bid': [4, 8], 'ask': [5, 8], 'accounts': [['a0', 'asset', False, 101, 500], ['a1', 'asset', True, 250, 250], ['a2', 'liability', True, 3, 3]]}, {'balances': [['a0', 500], ['a1', 125], ['a2', 2]], 'unrealized_gain': -124}], ['control 5', {'bid': [4, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', True, 1, 4], ['a1', 'liability', False, 5, 8], ['a2', 'liability', True, 3, 6], ['a3', 'liability', False, 3, 6]]}, {'balances': [['a0', 2], ['a1', 8], ['a2', 8], ['a3', 6]], 'unrealized_gain': -4}], ['control 6', {'bid': [17, 10], 'ask': [20, 10], 'accounts': [['a0', 'liability', True, 250, 250], ['a1', 'liability', False, 7, 500], ['a2', 'asset', True, 250, 250], ['a3', 'asset', True, 1000, 1000]]}, {'balances': [['a0', 500], ['a1', 500], ['a2', 425], ['a3', 1700]], 'unrealized_gain': 625}]], [['regression: delta baseline', {'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}], ['control 1', {'bid': [9, 4], 'ask': [10, 4], 'accounts': [['a0', 'asset', False, 1, 500], ['a1', 'liability', True, 999, 999]]}, {'balances': [['a0', 500], ['a1', 2498]], 'unrealized_gain': -1499}], ['control 2', {'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 3', {'bid': [4, 4], 'ask': [7, 4], 'accounts': [['a0', 'liability', False, 5, 8], ['a1', 'asset', False, 999, 1002], ['a2', 'asset', False, 7, 10], ['a3', 'liability', True, 7, 7]]}, {'balances': [['a0', 8], ['a1', 1002], ['a2', 10], ['a3', 12]], 'unrealized_gain': -5}], ['control 4', {'bid': [15, 10], 'ask': [18, 10], 'accounts': [['a0', 'liability', True, 250, 250], ['a1', 'asset', True, 7, 7]]}, {'balances': [['a0', 450], ['a1', 11]], 'unrealized_gain': -196}], ['control 5', {'bid': [4, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', False, 5, 5], ['a1', 'liability', True, 1000, 1000], ['a2', 'liability', True, 3, 3], ['a3', 'asset', False, 999, 999]]}, {'balances': [['a0', 5], ['a1', 2500], ['a2', 8], ['a3', 999]], 'unrealized_gain': -1505}], ['control 6', {'bid': [10, 8], 'ask': [13, 8], 'accounts': [['a0', 'liability', True, 1, 1], ['a1', 'liability', False, 1000, 2000]]}, {'balances': [['a0', 2], ['a1', 2000]], 'unrealized_gain': -1}]], [['regression: delta baseline', {'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}], ['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': [5, 10], 'ask': [8, 10], 'accounts': [['a0', 'liability', False, 101, 202], ['a1', 'liability', False, 1000, 1003], ['a2', 'liability', True, 5, 5], ['a3', 'asset', False, 5, 500], ['a4', 'liability', False, 101, 202]]}, {'balances': [['a0', 202], ['a1', 1003], ['a2', 4], ['a3', 500], ['a4', 202]], 'unrealized_gain': 1}], ['control 3', {'bid': [9, 8], 'ask': [10, 8], 'accounts': [['a0', 'asset', False, 250, 253], ['a1', 'liability', False, 101, 101], ['a2', 'liability', True, 3, 3], ['a3', 'liability', False, 3, 6], ['a4', 'liability', True, 1000, 1000]]}, {'balances': [['a0', 253], ['a1', 101], ['a2', 4], ['a3', 6], ['a4', 1250]], 'unrealized_gain': -251}], ['control 4', {'bid': [7, 8], 'ask': [8, 8], 'accounts': [['a0', 'asset', True, 7, 10], ['a1', 'liability', True, 3, 6], ['a2', 'liability', False, 101, 101], ['a3', 'liability', False, 1, 2]]}, {'balances': [['a0', 6], ['a1', 3], ['a2', 101], ['a3', 2]], 'unrealized_gain': -1}], ['control 5', {'bid': [127, 100], 'ask': [130, 100], 'accounts': [['a0', 'asset', False, 250, 250], ['a1', 'liability', True, 5, 5], ['a2', 'asset', False, 5, 500]]}, {'balances': [['a0', 250], ['a1', 7], ['a2', 500]], 'unrealized_gain': -2}], ['control 6', {'bid': [95, 100], 'ask': [98, 100], 'accounts': [['a0', 'asset', False, 1000, 1000], ['a1', 'asset', True, 250, 250]]}, {'balances': [['a0', 1000], ['a1', 238]], 'unrealized_gain': -12}]], [['regression: delta baseline', {'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}], ['control 1', {'bid': [14, 10], 'ask': [17, 10], 'accounts': [['a0', 'liability', True, 1, 4], ['a1', 'asset', True, 250, 253], ['a2', 'liability', False, 999, 1002], ['a3', 'asset', False, 7, 10], ['a4', 'asset', False, 101, 101]]}, {'balances': [['a0', 2], ['a1', 350], ['a2', 1002], ['a3', 10], ['a4', 101]], 'unrealized_gain': 99}], ['control 2', {'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 3', {'bid': [7, 10], 'ask': [9, 10], 'accounts': [['a0', 'asset', False, 250, 500], ['a1', 'asset', True, 250, 250], ['a2', 'asset', False, 7, 14]]}, {'balances': [['a0', 500], ['a1', 175], ['a2', 14]], 'unrealized_gain': -75}], ['control 4', {'bid': [15, 10], 'ask': [18, 10], 'accounts': [['a0', 'asset', True, 5, 5], ['a1', 'liability', False, 250, 250], ['a2', 'liability', False, 250, 500], ['a3', 'liability', False, 7, 500]]}, {'balances': [['a0', 8], ['a1', 250], ['a2', 500], ['a3', 500]], 'unrealized_gain': 3}], ['control 5', {'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 6', {'bid': [165, 100], 'ask': [166, 100], 'accounts': [['a0', 'liability', True, 7, 7], ['a1', 'asset', False, 250, 250]]}, {'balances': [['a0', 12], ['a1', 250]], 'unrealized_gain': -5}]], [['regression: delta baseline', {'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': [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 2', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', False, 7, 14], ['a1', 'asset', True, 7, 7], ['a2', 'liability', True, 101, 104], ['a3', 'asset', True, 3, 6]]}, {'balances': [['a0', 14], ['a1', 7], ['a2', 253], ['a3', 3]], 'unrealized_gain': -152}], ['control 3', {'bid': [7, 8], 'ask': [9, 8], 'accounts': [['a0', 'asset', True, 250, 253], ['a1', 'liability', True, 1, 4]]}, {'balances': [['a0', 219], ['a1', 1]], 'unrealized_gain': -31}], ['control 4', {'bid': [7, 8], 'ask': [9, 8], 'accounts': [['a0', 'liability', True, 7, 7], ['a1', 'asset', True, 250, 250], ['a2', 'liability', True, 1000, 1000], ['a3', 'asset', False, 250, 500]]}, {'balances': [['a0', 8], ['a1', 219], ['a2', 1125], ['a3', 500]], 'unrealized_gain': -157}], ['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: delta baseline{'balances': [['a0', 9], ['a1', 7], ['a2', 6]], 'unrealized_gain': -3}{'balances': [['a0', 9], ['a1', 7], ['a2', 6]], 'unrealized_gain': 7}Failed
control 1{'balances': [['a0', 2000], ['a1', 7], ['a2', 500], ['a3', 8], ['a4', 1000]], 'unrealized_gain': 1250}{'balances': [['a0', 2000], ['a1', 7], ['a2', 500], ['a3', 8], ['a4', 1000]], 'unrealized_gain': 1250}Passed
control 2{'balances': [['a0', 63], ['a1', 4]], 'unrealized_gain': -38}{'balances': [['a0', 63], ['a1', 4]], 'unrealized_gain': -38}Passed
control 3{'balances': [['a0', 104], ['a1', 10], ['a2', 12], ['a3', 14]], 'unrealized_gain': -7}{'balances': [['a0', 104], ['a1', 10], ['a2', 12], ['a3', 14]], 'unrealized_gain': -7}Passed
control 4{'balances': [['a0', 500], ['a1', 125], ['a2', 2]], 'unrealized_gain': -124}{'balances': [['a0', 500], ['a1', 125], ['a2', 2]], 'unrealized_gain': -124}Passed
control 5{'balances': [['a0', 2], ['a1', 8], ['a2', 8], ['a3', 6]], 'unrealized_gain': -4}{'balances': [['a0', 2], ['a1', 8], ['a2', 8], ['a3', 6]], 'unrealized_gain': -4}Passed
control 6{'balances': [['a0', 500], ['a1', 500], ['a2', 425], ['a3', 1700]], 'unrealized_gain': 625}{'balances': [['a0', 500], ['a1', 500], ['a2', 425], ['a3', 1700]], 'unrealized_gain': 625}Passed

SHA-256 / c4d9ab89d9909649fc06e1ecf84c98aa486373a223bfbaf89ccd2ba5a1f251cd

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)
        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 - to_home(carried, rate)
        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: delta baseline', {'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': [8, 4], 'ask': [11, 4], 'accounts': [['a0', 'asset', True, 1000, 1000], ['a1', 'asset', False, 7, 7], ['a2', 'asset', True, 250, 250], ['a3', 'liability', False, 5, 8], ['a4', 'liability', False, 1000, 1000]]}, {'balances': [['a0', 2000], ['a1', 7], ['a2', 500], ['a3', 8], ['a4', 1000]], 'unrealized_gain': 1250}], ['control 2', {'bid': [5, 8], 'ask': [6, 8], 'accounts': [['a0', 'asset', True, 101, 101], ['a1', 'asset', False, 1, 4]]}, {'balances': [['a0', 63], ['a1', 4]], 'unrealized_gain': -38}], ['control 3', {'bid': [17, 10], 'ask': [20, 10], 'accounts': [['a0', 'asset', False, 101, 104], ['a1', 'liability', True, 5, 5], ['a2', 'asset', True, 7, 500], ['a3', 'liability', True, 7, 500]]}, {'balances': [['a0', 104], ['a1', 10], ['a2', 12], ['a3', 14]], 'unrealized_gain': -7}], ['control 4', {'bid': [4, 8], 'ask': [5, 8], 'accounts': [['a0', 'asset', False, 101, 500], ['a1', 'asset', True, 250, 250], ['a2', 'liability', True, 3, 3]]}, {'balances': [['a0', 500], ['a1', 125], ['a2', 2]], 'unrealized_gain': -124}], ['control 5', {'bid': [4, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', True, 1, 4], ['a1', 'liability', False, 5, 8], ['a2', 'liability', True, 3, 6], ['a3', 'liability', False, 3, 6]]}, {'balances': [['a0', 2], ['a1', 8], ['a2', 8], ['a3', 6]], 'unrealized_gain': -4}], ['control 6', {'bid': [17, 10], 'ask': [20, 10], 'accounts': [['a0', 'liability', True, 250, 250], ['a1', 'liability', False, 7, 500], ['a2', 'asset', True, 250, 250], ['a3', 'asset', True, 1000, 1000]]}, {'balances': [['a0', 500], ['a1', 500], ['a2', 425], ['a3', 1700]], 'unrealized_gain': 625}]], [['regression: delta baseline', {'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}], ['control 1', {'bid': [9, 4], 'ask': [10, 4], 'accounts': [['a0', 'asset', False, 1, 500], ['a1', 'liability', True, 999, 999]]}, {'balances': [['a0', 500], ['a1', 2498]], 'unrealized_gain': -1499}], ['control 2', {'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 3', {'bid': [4, 4], 'ask': [7, 4], 'accounts': [['a0', 'liability', False, 5, 8], ['a1', 'asset', False, 999, 1002], ['a2', 'asset', False, 7, 10], ['a3', 'liability', True, 7, 7]]}, {'balances': [['a0', 8], ['a1', 1002], ['a2', 10], ['a3', 12]], 'unrealized_gain': -5}], ['control 4', {'bid': [15, 10], 'ask': [18, 10], 'accounts': [['a0', 'liability', True, 250, 250], ['a1', 'asset', True, 7, 7]]}, {'balances': [['a0', 450], ['a1', 11]], 'unrealized_gain': -196}], ['control 5', {'bid': [4, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', False, 5, 5], ['a1', 'liability', True, 1000, 1000], ['a2', 'liability', True, 3, 3], ['a3', 'asset', False, 999, 999]]}, {'balances': [['a0', 5], ['a1', 2500], ['a2', 8], ['a3', 999]], 'unrealized_gain': -1505}], ['control 6', {'bid': [10, 8], 'ask': [13, 8], 'accounts': [['a0', 'liability', True, 1, 1], ['a1', 'liability', False, 1000, 2000]]}, {'balances': [['a0', 2], ['a1', 2000]], 'unrealized_gain': -1}]], [['regression: delta baseline', {'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}], ['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': [5, 10], 'ask': [8, 10], 'accounts': [['a0', 'liability', False, 101, 202], ['a1', 'liability', False, 1000, 1003], ['a2', 'liability', True, 5, 5], ['a3', 'asset', False, 5, 500], ['a4', 'liability', False, 101, 202]]}, {'balances': [['a0', 202], ['a1', 1003], ['a2', 4], ['a3', 500], ['a4', 202]], 'unrealized_gain': 1}], ['control 3', {'bid': [9, 8], 'ask': [10, 8], 'accounts': [['a0', 'asset', False, 250, 253], ['a1', 'liability', False, 101, 101], ['a2', 'liability', True, 3, 3], ['a3', 'liability', False, 3, 6], ['a4', 'liability', True, 1000, 1000]]}, {'balances': [['a0', 253], ['a1', 101], ['a2', 4], ['a3', 6], ['a4', 1250]], 'unrealized_gain': -251}], ['control 4', {'bid': [7, 8], 'ask': [8, 8], 'accounts': [['a0', 'asset', True, 7, 10], ['a1', 'liability', True, 3, 6], ['a2', 'liability', False, 101, 101], ['a3', 'liability', False, 1, 2]]}, {'balances': [['a0', 6], ['a1', 3], ['a2', 101], ['a3', 2]], 'unrealized_gain': -1}], ['control 5', {'bid': [127, 100], 'ask': [130, 100], 'accounts': [['a0', 'asset', False, 250, 250], ['a1', 'liability', True, 5, 5], ['a2', 'asset', False, 5, 500]]}, {'balances': [['a0', 250], ['a1', 7], ['a2', 500]], 'unrealized_gain': -2}], ['control 6', {'bid': [95, 100], 'ask': [98, 100], 'accounts': [['a0', 'asset', False, 1000, 1000], ['a1', 'asset', True, 250, 250]]}, {'balances': [['a0', 1000], ['a1', 238]], 'unrealized_gain': -12}]], [['regression: delta baseline', {'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}], ['control 1', {'bid': [14, 10], 'ask': [17, 10], 'accounts': [['a0', 'liability', True, 1, 4], ['a1', 'asset', True, 250, 253], ['a2', 'liability', False, 999, 1002], ['a3', 'asset', False, 7, 10], ['a4', 'asset', False, 101, 101]]}, {'balances': [['a0', 2], ['a1', 350], ['a2', 1002], ['a3', 10], ['a4', 101]], 'unrealized_gain': 99}], ['control 2', {'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 3', {'bid': [7, 10], 'ask': [9, 10], 'accounts': [['a0', 'asset', False, 250, 500], ['a1', 'asset', True, 250, 250], ['a2', 'asset', False, 7, 14]]}, {'balances': [['a0', 500], ['a1', 175], ['a2', 14]], 'unrealized_gain': -75}], ['control 4', {'bid': [15, 10], 'ask': [18, 10], 'accounts': [['a0', 'asset', True, 5, 5], ['a1', 'liability', False, 250, 250], ['a2', 'liability', False, 250, 500], ['a3', 'liability', False, 7, 500]]}, {'balances': [['a0', 8], ['a1', 250], ['a2', 500], ['a3', 500]], 'unrealized_gain': 3}], ['control 5', {'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 6', {'bid': [165, 100], 'ask': [166, 100], 'accounts': [['a0', 'liability', True, 7, 7], ['a1', 'asset', False, 250, 250]]}, {'balances': [['a0', 12], ['a1', 250]], 'unrealized_gain': -5}]], [['regression: delta baseline', {'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': [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 2', {'bid': [2, 2], 'ask': [5, 2], 'accounts': [['a0', 'asset', False, 7, 14], ['a1', 'asset', True, 7, 7], ['a2', 'liability', True, 101, 104], ['a3', 'asset', True, 3, 6]]}, {'balances': [['a0', 14], ['a1', 7], ['a2', 253], ['a3', 3]], 'unrealized_gain': -152}], ['control 3', {'bid': [7, 8], 'ask': [9, 8], 'accounts': [['a0', 'asset', True, 250, 253], ['a1', 'liability', True, 1, 4]]}, {'balances': [['a0', 219], ['a1', 1]], 'unrealized_gain': -31}], ['control 4', {'bid': [7, 8], 'ask': [9, 8], 'accounts': [['a0', 'liability', True, 7, 7], ['a1', 'asset', True, 250, 250], ['a2', 'liability', True, 1000, 1000], ['a3', 'asset', False, 250, 500]]}, {'balances': [['a0', 8], ['a1', 219], ['a2', 1125], ['a3', 500]], 'unrealized_gain': -157}], ['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: delta baseline{'balances': [['a0', 9], ['a1', 7], ['a2', 6]], 'unrealized_gain': 13}{'balances': [['a0', 9], ['a1', 7], ['a2', 6]], 'unrealized_gain': 7}Failed
control 1{'balances': [['a0', 2000], ['a1', 7], ['a2', 500], ['a3', 8], ['a4', 1000]], 'unrealized_gain': 0}{'balances': [['a0', 2000], ['a1', 7], ['a2', 500], ['a3', 8], ['a4', 1000]], 'unrealized_gain': 1250}Failed
control 2{'balances': [['a0', 63], ['a1', 4]], 'unrealized_gain': 0}{'balances': [['a0', 63], ['a1', 4]], 'unrealized_gain': -38}Failed
control 3{'balances': [['a0', 104], ['a1', 10], ['a2', 12], ['a3', 14]], 'unrealized_gain': 148}{'balances': [['a0', 104], ['a1', 10], ['a2', 12], ['a3', 14]], 'unrealized_gain': -7}Failed
control 4{'balances': [['a0', 500], ['a1', 125], ['a2', 2]], 'unrealized_gain': 0}{'balances': [['a0', 500], ['a1', 125], ['a2', 2]], 'unrealized_gain': -124}Failed
control 5{'balances': [['a0', 2], ['a1', 8], ['a2', 8], ['a3', 6]], 'unrealized_gain': 1}{'balances': [['a0', 2], ['a1', 8], ['a2', 8], ['a3', 6]], 'unrealized_gain': -4}Failed
control 6{'balances': [['a0', 500], ['a1', 500], ['a2', 425], ['a3', 1700]], 'unrealized_gain': 0}{'balances': [['a0', 500], ['a1', 500], ['a2', 425], ['a3', 1700]], 'unrealized_gain': 625}Failed

SHA-256 / 942bba392e1e153ed87cc241c8443d3ce08de41407e0eea8e350db227a6d792f

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.

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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 2026-09-29T14:46:22.513374+00:00.

Case digest / 09d6f5b797e335d04be4f394a6ac8267a055cec43e2f36680e506dcf182c7977