FA-68631 / Toll and parking fee computation / Open access

Prepaid toll account auto-replenishment: the negative index is overwritten by later charges · case 01

Prepaid toll account auto-replenishment returns a wrong result when the negative index is overwritten by later charges.

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

ROOT CAUSE

Without the latch the last negative charge is reported instead of the first.

VERIFIED REPAIR

Restore the first negative latch rule so that the step reads `if bal < 0 and first is None:`.

Unsuccessful approach: Counting a zero balance as negative flags accounts that are exactly empty.

Case contract

Input {balance, charges, threshold, min_replenish, usage_30d, card_ok}. The replenish amount is max(min_replenish, ceil(usage_30d/4) rounded up to a multiple of 500). After each charge, if the balance is strictly below threshold and the card works, one replenishment is added. first_negative is the index of the first charge after which the balance is negative (or null). Return {balance, replenished, first_negative}.

Why this case matters

Fee engines bill customers in integer cents; a wrong boundary, rounding stage or cap scope silently over- or under-charges.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(x):
    bal = x['balance']
    n = 0
    first = None
    amt = max(x['min_replenish'], -(-x['usage_30d'] // 2000) * 500)
    for i, c in enumerate(x['charges']):
        bal -= c
        if bal < x['threshold'] and x['card_ok']:
            bal += amt
            n += 1
        if bal < 0:
            first = i
    return {'balance': bal, 'replenished': n, 'first_negative': first}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'balance': 1322, 'charges': [650], 'threshold': 1000, 'min_replenish': 2000, 'usage_30d': 18596, 'card_ok': True}, {'balance': 5672, 'replenished': 1, 'first_negative': None}), ({'balance': 994, 'charges': [3000, 400, 3000, 650, 3000, 3000, 275], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 16149, 'card_ok': True}, {'balance': 1169, 'replenished': 3, 'first_negative': None}), ({'balance': 921, 'charges': [1200, 650, 650, 150, 1200, 400, 1200, 150], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 11909, 'card_ok': False}, {'balance': -4679, 'replenished': 0, 'first_negative': 0}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 3320, 'charges': [3000, 3000, 3000, 400, 3000], 'threshold': 500, 'min_replenish': 2500, 'usage_30d': 7303, 'card_ok': False}, {'balance': -9080, 'replenished': 0, 'first_negative': 1}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 2429, 'charges': [275, 150, 275, 150, 150, 400, 1200], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 6810, 'card_ok': True}, {'balance': 2329, 'replenished': 1, 'first_negative': None})], [({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 753, 'charges': [650, 3000], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 2408, 'card_ok': False}, {'balance': -2897, 'replenished': 0, 'first_negative': 1}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 1987, 'charges': [275, 1200, 150, 400], 'threshold': 1000, 'min_replenish': 2000, 'usage_30d': 17952, 'card_ok': True}, {'balance': 4462, 'replenished': 1, 'first_negative': None}), ({'balance': 3568, 'charges': [150, 1200, 150, 3000, 275, 650], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 16196, 'card_ok': False}, {'balance': -1857, 'replenished': 0, 'first_negative': 3}), ({'balance': 616, 'charges': [1200, 275, 275, 650, 275], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 5115, 'card_ok': False}, {'balance': -2059, 'replenished': 0, 'first_negative': 0}), ({'balance': 1428, 'charges': [275, 3000, 1200, 650, 3000, 3000, 1200], 'threshold': 500, 'min_replenish': 2000, 'usage_30d': 12671, 'card_ok': True}, {'balance': 3103, 'replenished': 4, 'first_negative': None})], [({'balance': 390, 'charges': [400, 1200], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 1137, 'card_ok': False}, {'balance': -1210, 'replenished': 0, 'first_negative': 0}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 1694, 'charges': [275, 1200, 275, 275, 650], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 904, 'card_ok': False}, {'balance': -981, 'replenished': 0, 'first_negative': 2}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 2427, 'charges': [400, 400, 400, 3000, 650], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 2179, 'card_ok': True}, {'balance': -423, 'replenished': 2, 'first_negative': 3}), ({'balance': 1802, 'charges': [650], 'threshold': 500, 'min_replenish': 2000, 'usage_30d': 19640, 'card_ok': True}, {'balance': 1152, 'replenished': 0, 'first_negative': None}), ({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 155, 'charges': [400, 650, 275, 650], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 2650, 'card_ok': True}, {'balance': 3180, 'replenished': 2, 'first_negative': None})], [({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 1910, 'charges': [275, 400, 3000, 1200, 400], 'threshold': 500, 'min_replenish': 2000, 'usage_30d': 12496, 'card_ok': True}, {'balance': 3635, 'replenished': 2, 'first_negative': None}), ({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 2190, 'charges': [275], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 15361, 'card_ok': True}, {'balance': 1915, 'replenished': 0, 'first_negative': None}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 3344, 'charges': [650, 3000, 1200, 1200, 3000], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 104, 'card_ok': True}, {'balance': -1706, 'replenished': 4, 'first_negative': 4}), ({'balance': -397, 'charges': [1200, 1200, 400, 1200, 1200, 275, 150], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 452, 'card_ok': False}, {'balance': -6022, 'replenished': 0, 'first_negative': 0}), ({'balance': 2655, 'charges': [650, 3000, 275], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 9407, 'card_ok': False}, {'balance': -1270, 'replenished': 0, 'first_negative': 1})], [({'balance': 2215, 'charges': [3000, 150, 275], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 16466, 'card_ok': False}, {'balance': -1210, 'replenished': 0, 'first_negative': 0}), ({'balance': 261, 'charges': [3000, 1200, 1200], 'threshold': 500, 'min_replenish': 2000, 'usage_30d': 11452, 'card_ok': True}, {'balance': 861, 'replenished': 2, 'first_negative': None}), ({'balance': -14, 'charges': [1200, 275, 400, 650, 650, 650], 'threshold': 500, 'min_replenish': 2000, 'usage_30d': 6151, 'card_ok': True}, {'balance': 2161, 'replenished': 3, 'first_negative': None}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 3175, 'charges': [1200, 650, 400, 650, 275, 400, 3000], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 15568, 'card_ok': False}, {'balance': -3400, 'replenished': 0, 'first_negative': 5}), ({'balance': -156, 'charges': [275, 1200], 'threshold': 1000, 'min_replenish': 2000, 'usage_30d': 11597, 'card_ok': False}, {'balance': -1631, 'replenished': 0, 'first_negative': 0}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0})]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check('fee oracle' + ' %d' % 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 fixture	Actual	Expected	Outcome
fee oracle 0	`{'balance': 5672, 'first_negative': None, 'replenished': 1}`	`{'balance': 5672, 'first_negative': None, 'replenished': 1}`	Passed
fee oracle 1	`{'balance': 1169, 'first_negative': None, 'replenished': 3}`	`{'balance': 1169, 'first_negative': None, 'replenished': 3}`	Passed
fee oracle 2	`{'balance': -4679, 'first_negative': 7, 'replenished': 0}`	`{'balance': -4679, 'first_negative': 0, 'replenished': 0}`	Failed
fee oracle 3	`{'balance': 0, 'first_negative': None, 'replenished': 0}`	`{'balance': 0, 'first_negative': None, 'replenished': 0}`	Passed
fee oracle 4	`{'balance': -9080, 'first_negative': 4, 'replenished': 0}`	`{'balance': -9080, 'first_negative': 1, 'replenished': 0}`	Failed
fee oracle 5	`{'balance': 1000, 'first_negative': None, 'replenished': 0}`	`{'balance': 1000, 'first_negative': None, 'replenished': 0}`	Passed
fee oracle 6	`{'balance': -525, 'first_negative': 2, 'replenished': 0}`	`{'balance': -525, 'first_negative': 0, 'replenished': 0}`	Failed
fee oracle 7	`{'balance': 2329, 'first_negative': None, 'replenished': 1}`	`{'balance': 2329, 'first_negative': None, 'replenished': 1}`	Passed

SHA-256 / 335e96c0e32f05a7524d6d254f13511f19348f694c91f0f84f34dae89c303a6d

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(x):
    bal = x['balance']
    n = 0
    first = None
    amt = max(x['min_replenish'], -(-x['usage_30d'] // 2000) * 500)
    for i, c in enumerate(x['charges']):
        bal -= c
        if bal < x['threshold'] and x['card_ok']:
            bal += amt
            n += 1
        if bal <= 0 and first is None:
            first = i
    return {'balance': bal, 'replenished': n, 'first_negative': first}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'balance': 1322, 'charges': [650], 'threshold': 1000, 'min_replenish': 2000, 'usage_30d': 18596, 'card_ok': True}, {'balance': 5672, 'replenished': 1, 'first_negative': None}), ({'balance': 994, 'charges': [3000, 400, 3000, 650, 3000, 3000, 275], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 16149, 'card_ok': True}, {'balance': 1169, 'replenished': 3, 'first_negative': None}), ({'balance': 921, 'charges': [1200, 650, 650, 150, 1200, 400, 1200, 150], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 11909, 'card_ok': False}, {'balance': -4679, 'replenished': 0, 'first_negative': 0}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 3320, 'charges': [3000, 3000, 3000, 400, 3000], 'threshold': 500, 'min_replenish': 2500, 'usage_30d': 7303, 'card_ok': False}, {'balance': -9080, 'replenished': 0, 'first_negative': 1}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 2429, 'charges': [275, 150, 275, 150, 150, 400, 1200], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 6810, 'card_ok': True}, {'balance': 2329, 'replenished': 1, 'first_negative': None})], [({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 753, 'charges': [650, 3000], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 2408, 'card_ok': False}, {'balance': -2897, 'replenished': 0, 'first_negative': 1}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 1987, 'charges': [275, 1200, 150, 400], 'threshold': 1000, 'min_replenish': 2000, 'usage_30d': 17952, 'card_ok': True}, {'balance': 4462, 'replenished': 1, 'first_negative': None}), ({'balance': 3568, 'charges': [150, 1200, 150, 3000, 275, 650], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 16196, 'card_ok': False}, {'balance': -1857, 'replenished': 0, 'first_negative': 3}), ({'balance': 616, 'charges': [1200, 275, 275, 650, 275], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 5115, 'card_ok': False}, {'balance': -2059, 'replenished': 0, 'first_negative': 0}), ({'balance': 1428, 'charges': [275, 3000, 1200, 650, 3000, 3000, 1200], 'threshold': 500, 'min_replenish': 2000, 'usage_30d': 12671, 'card_ok': True}, {'balance': 3103, 'replenished': 4, 'first_negative': None})], [({'balance': 390, 'charges': [400, 1200], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 1137, 'card_ok': False}, {'balance': -1210, 'replenished': 0, 'first_negative': 0}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 1694, 'charges': [275, 1200, 275, 275, 650], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 904, 'card_ok': False}, {'balance': -981, 'replenished': 0, 'first_negative': 2}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 2427, 'charges': [400, 400, 400, 3000, 650], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 2179, 'card_ok': True}, {'balance': -423, 'replenished': 2, 'first_negative': 3}), ({'balance': 1802, 'charges': [650], 'threshold': 500, 'min_replenish': 2000, 'usage_30d': 19640, 'card_ok': True}, {'balance': 1152, 'replenished': 0, 'first_negative': None}), ({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 155, 'charges': [400, 650, 275, 650], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 2650, 'card_ok': True}, {'balance': 3180, 'replenished': 2, 'first_negative': None})], [({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 1910, 'charges': [275, 400, 3000, 1200, 400], 'threshold': 500, 'min_replenish': 2000, 'usage_30d': 12496, 'card_ok': True}, {'balance': 3635, 'replenished': 2, 'first_negative': None}), ({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 2190, 'charges': [275], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 15361, 'card_ok': True}, {'balance': 1915, 'replenished': 0, 'first_negative': None}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 3344, 'charges': [650, 3000, 1200, 1200, 3000], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 104, 'card_ok': True}, {'balance': -1706, 'replenished': 4, 'first_negative': 4}), ({'balance': -397, 'charges': [1200, 1200, 400, 1200, 1200, 275, 150], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 452, 'card_ok': False}, {'balance': -6022, 'replenished': 0, 'first_negative': 0}), ({'balance': 2655, 'charges': [650, 3000, 275], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 9407, 'card_ok': False}, {'balance': -1270, 'replenished': 0, 'first_negative': 1})], [({'balance': 2215, 'charges': [3000, 150, 275], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 16466, 'card_ok': False}, {'balance': -1210, 'replenished': 0, 'first_negative': 0}), ({'balance': 261, 'charges': [3000, 1200, 1200], 'threshold': 500, 'min_replenish': 2000, 'usage_30d': 11452, 'card_ok': True}, {'balance': 861, 'replenished': 2, 'first_negative': None}), ({'balance': -14, 'charges': [1200, 275, 400, 650, 650, 650], 'threshold': 500, 'min_replenish': 2000, 'usage_30d': 6151, 'card_ok': True}, {'balance': 2161, 'replenished': 3, 'first_negative': None}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 3175, 'charges': [1200, 650, 400, 650, 275, 400, 3000], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 15568, 'card_ok': False}, {'balance': -3400, 'replenished': 0, 'first_negative': 5}), ({'balance': -156, 'charges': [275, 1200], 'threshold': 1000, 'min_replenish': 2000, 'usage_30d': 11597, 'card_ok': False}, {'balance': -1631, 'replenished': 0, 'first_negative': 0}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0})]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check('fee oracle' + ' %d' % 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 fixture	Actual	Expected	Outcome
fee oracle 0	`{'balance': 5672, 'first_negative': None, 'replenished': 1}`	`{'balance': 5672, 'first_negative': None, 'replenished': 1}`	Passed
fee oracle 1	`{'balance': 1169, 'first_negative': None, 'replenished': 3}`	`{'balance': 1169, 'first_negative': None, 'replenished': 3}`	Passed
fee oracle 2	`{'balance': -4679, 'first_negative': 0, 'replenished': 0}`	`{'balance': -4679, 'first_negative': 0, 'replenished': 0}`	Passed
fee oracle 3	`{'balance': 0, 'first_negative': 0, 'replenished': 0}`	`{'balance': 0, 'first_negative': None, 'replenished': 0}`	Failed
fee oracle 4	`{'balance': -9080, 'first_negative': 1, 'replenished': 0}`	`{'balance': -9080, 'first_negative': 1, 'replenished': 0}`	Passed
fee oracle 5	`{'balance': 1000, 'first_negative': None, 'replenished': 0}`	`{'balance': 1000, 'first_negative': None, 'replenished': 0}`	Passed
fee oracle 6	`{'balance': -525, 'first_negative': 0, 'replenished': 0}`	`{'balance': -525, 'first_negative': 0, 'replenished': 0}`	Passed
fee oracle 7	`{'balance': 2329, 'first_negative': None, 'replenished': 1}`	`{'balance': 2329, 'first_negative': None, 'replenished': 1}`	Passed

SHA-256 / fd6731dd6321e7b1314eea9f2cce750a91b185a8f3f59fbbccb1d74bbc22f055

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(x):
    bal = x['balance']
    n = 0
    first = None
    amt = max(x['min_replenish'], -(-x['usage_30d'] // 2000) * 500)
    for i, c in enumerate(x['charges']):
        bal -= c
        if bal < x['threshold'] and x['card_ok']:
            bal += amt
            n += 1
        if bal < 0 and first is None:
            first = i
    return {'balance': bal, 'replenished': n, 'first_negative': first}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'balance': 1322, 'charges': [650], 'threshold': 1000, 'min_replenish': 2000, 'usage_30d': 18596, 'card_ok': True}, {'balance': 5672, 'replenished': 1, 'first_negative': None}), ({'balance': 994, 'charges': [3000, 400, 3000, 650, 3000, 3000, 275], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 16149, 'card_ok': True}, {'balance': 1169, 'replenished': 3, 'first_negative': None}), ({'balance': 921, 'charges': [1200, 650, 650, 150, 1200, 400, 1200, 150], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 11909, 'card_ok': False}, {'balance': -4679, 'replenished': 0, 'first_negative': 0}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 3320, 'charges': [3000, 3000, 3000, 400, 3000], 'threshold': 500, 'min_replenish': 2500, 'usage_30d': 7303, 'card_ok': False}, {'balance': -9080, 'replenished': 0, 'first_negative': 1}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 2429, 'charges': [275, 150, 275, 150, 150, 400, 1200], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 6810, 'card_ok': True}, {'balance': 2329, 'replenished': 1, 'first_negative': None})], [({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 753, 'charges': [650, 3000], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 2408, 'card_ok': False}, {'balance': -2897, 'replenished': 0, 'first_negative': 1}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 1987, 'charges': [275, 1200, 150, 400], 'threshold': 1000, 'min_replenish': 2000, 'usage_30d': 17952, 'card_ok': True}, {'balance': 4462, 'replenished': 1, 'first_negative': None}), ({'balance': 3568, 'charges': [150, 1200, 150, 3000, 275, 650], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 16196, 'card_ok': False}, {'balance': -1857, 'replenished': 0, 'first_negative': 3}), ({'balance': 616, 'charges': [1200, 275, 275, 650, 275], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 5115, 'card_ok': False}, {'balance': -2059, 'replenished': 0, 'first_negative': 0}), ({'balance': 1428, 'charges': [275, 3000, 1200, 650, 3000, 3000, 1200], 'threshold': 500, 'min_replenish': 2000, 'usage_30d': 12671, 'card_ok': True}, {'balance': 3103, 'replenished': 4, 'first_negative': None})], [({'balance': 390, 'charges': [400, 1200], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 1137, 'card_ok': False}, {'balance': -1210, 'replenished': 0, 'first_negative': 0}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 1694, 'charges': [275, 1200, 275, 275, 650], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 904, 'card_ok': False}, {'balance': -981, 'replenished': 0, 'first_negative': 2}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 2427, 'charges': [400, 400, 400, 3000, 650], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 2179, 'card_ok': True}, {'balance': -423, 'replenished': 2, 'first_negative': 3}), ({'balance': 1802, 'charges': [650], 'threshold': 500, 'min_replenish': 2000, 'usage_30d': 19640, 'card_ok': True}, {'balance': 1152, 'replenished': 0, 'first_negative': None}), ({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 155, 'charges': [400, 650, 275, 650], 'threshold': 1000, 'min_replenish': 2500, 'usage_30d': 2650, 'card_ok': True}, {'balance': 3180, 'replenished': 2, 'first_negative': None})], [({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 1910, 'charges': [275, 400, 3000, 1200, 400], 'threshold': 500, 'min_replenish': 2000, 'usage_30d': 12496, 'card_ok': True}, {'balance': 3635, 'replenished': 2, 'first_negative': None}), ({'balance': 1400, 'charges': [400, 150], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 3350, 'replenished': 1, 'first_negative': None}), ({'balance': 2190, 'charges': [275], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 15361, 'card_ok': True}, {'balance': 1915, 'replenished': 0, 'first_negative': None}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0}), ({'balance': 3344, 'charges': [650, 3000, 1200, 1200, 3000], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 104, 'card_ok': True}, {'balance': -1706, 'replenished': 4, 'first_negative': 4}), ({'balance': -397, 'charges': [1200, 1200, 400, 1200, 1200, 275, 150], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 452, 'card_ok': False}, {'balance': -6022, 'replenished': 0, 'first_negative': 0}), ({'balance': 2655, 'charges': [650, 3000, 275], 'threshold': 1500, 'min_replenish': 2500, 'usage_30d': 9407, 'card_ok': False}, {'balance': -1270, 'replenished': 0, 'first_negative': 1})], [({'balance': 2215, 'charges': [3000, 150, 275], 'threshold': 1500, 'min_replenish': 2000, 'usage_30d': 16466, 'card_ok': False}, {'balance': -1210, 'replenished': 0, 'first_negative': 0}), ({'balance': 261, 'charges': [3000, 1200, 1200], 'threshold': 500, 'min_replenish': 2000, 'usage_30d': 11452, 'card_ok': True}, {'balance': 861, 'replenished': 2, 'first_negative': None}), ({'balance': -14, 'charges': [1200, 275, 400, 650, 650, 650], 'threshold': 500, 'min_replenish': 2000, 'usage_30d': 6151, 'card_ok': True}, {'balance': 2161, 'replenished': 3, 'first_negative': None}), ({'balance': 400, 'charges': [400], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': 0, 'replenished': 0, 'first_negative': None}), ({'balance': 3175, 'charges': [1200, 650, 400, 650, 275, 400, 3000], 'threshold': 1500, 'min_replenish': 1000, 'usage_30d': 15568, 'card_ok': False}, {'balance': -3400, 'replenished': 0, 'first_negative': 5}), ({'balance': -156, 'charges': [275, 1200], 'threshold': 1000, 'min_replenish': 2000, 'usage_30d': 11597, 'card_ok': False}, {'balance': -1631, 'replenished': 0, 'first_negative': 0}), ({'balance': 1400, 'charges': [400], 'threshold': 1000, 'min_replenish': 1000, 'usage_30d': 9000, 'card_ok': True}, {'balance': 1000, 'replenished': 0, 'first_negative': None}), ({'balance': 300, 'charges': [400, 150, 275], 'threshold': 500, 'min_replenish': 1000, 'usage_30d': 0, 'card_ok': False}, {'balance': -525, 'replenished': 0, 'first_negative': 0})]]
for i, (args, expected) in enumerate(fixtures[N-1]):
    check('fee oracle' + ' %d' % 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 fixture	Actual	Expected	Outcome
fee oracle 0	`{'balance': 5672, 'first_negative': None, 'replenished': 1}`	`{'balance': 5672, 'first_negative': None, 'replenished': 1}`	Passed
fee oracle 1	`{'balance': 1169, 'first_negative': None, 'replenished': 3}`	`{'balance': 1169, 'first_negative': None, 'replenished': 3}`	Passed
fee oracle 2	`{'balance': -4679, 'first_negative': 0, 'replenished': 0}`	`{'balance': -4679, 'first_negative': 0, 'replenished': 0}`	Passed
fee oracle 3	`{'balance': 0, 'first_negative': None, 'replenished': 0}`	`{'balance': 0, 'first_negative': None, 'replenished': 0}`	Passed
fee oracle 4	`{'balance': -9080, 'first_negative': 1, 'replenished': 0}`	`{'balance': -9080, 'first_negative': 1, 'replenished': 0}`	Passed
fee oracle 5	`{'balance': 1000, 'first_negative': None, 'replenished': 0}`	`{'balance': 1000, 'first_negative': None, 'replenished': 0}`	Passed
fee oracle 6	`{'balance': -525, 'first_negative': 0, 'replenished': 0}`	`{'balance': -525, 'first_negative': 0, 'replenished': 0}`	Passed
fee oracle 7	`{'balance': 2329, 'first_negative': None, 'replenished': 1}`	`{'balance': 2329, 'first_negative': None, 'replenished': 1}`	Passed

SHA-256 / f11ee9f73687c09e795204895896075c3d3c3000ac54cbac71c62004d4738fed

Verification & scope

A deterministic, bounded toy model with a stipulated contract; it makes no claim of conformance to any agency manual or standard. 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 2026-09-29T14:48:04.096372+00:00.

Case digest / 5233e222df5c3d388619ca293d76c5af42e6c47ccff8cc331574c6006bcd4e5f