FAILURE MAP
← Case archive

FA-68476 / Toll and parking fee computation / Open access

Street meter time purchase: the accepted amount truncates partial minutes of charge · case 01

Street meter time purchase returns a wrong result when the accepted amount truncates partial minutes of charge.

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

ROOT CAUSE

Rounding the accepted amount down refunds a fraction of a cent the customer used.

VERIFIED REPAIR

Restore the accepted amount rule so that the step reads `-(-used * x['rate_per_hour'] // 60)`.

Unsuccessful approach: Keeping the whole payment ignores time that was clipped by the limit or enforcement end.

Case contract

Input {now, expiry (or null), paid_cents, rate_per_hour, max_minutes, enf_start, enf_end, increment}. Only whole increments are credited. At or after enforcement end nothing is sold: [null, 0]. Paid time starts at the later of now, enforcement start and any unexpired expiry; it ends at the earliest of start + purchased minutes (floor), max(now, enf_start) + max_minutes, and enf_end. Accepted cents = min(credited, ceil(used minutes * rate/60)). Return [new expiry, accepted cents].

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):
    inc = x['increment']
    c = x['paid_cents'] - x['paid_cents'] % inc
    now = x['now']
    if now >= x['enf_end']:
        return [None, 0]
    base = max(now, x['enf_start'])
    start = base if x['expiry'] is None else max(base, x['expiry'])
    mins = c * 60 // x['rate_per_hour']
    end = min(start + mins, base + x['max_minutes'], x['enf_end'])
    used = max(0, end - start)
    cost = min(c, used * x['rate_per_hour'] // 60)
    return [max(end, start), cost]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'now': 1080, 'expiry': None, 'paid_cents': 342, 'rate_per_hour': 200, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 853, 'expiry': None, 'paid_cents': 395, 'rate_per_hour': 250, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [947, 392]), ({'now': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234]), ({'now': 491, 'expiry': None, 'paid_cents': 211, 'rate_per_hour': 250, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [541, 209]), ({'now': 880, 'expiry': None, 'paid_cents': 102, 'rate_per_hour': 250, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [904, 100]), ({'now': 420, 'expiry': None, 'paid_cents': 200, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 200]), ({'now': 1048, 'expiry': 1120, 'paid_cents': 599, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1120, 0]), ({'now': 1040, 'expiry': None, 'paid_cents': 333, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 100])], [({'now': 783, 'expiry': None, 'paid_cents': 518, 'rate_per_hour': 250, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [906, 513]), ({'now': 420, 'expiry': None, 'paid_cents': 200, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 200]), ({'now': 1040, 'expiry': None, 'paid_cents': 333, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 100]), ({'now': 608, 'expiry': 560, 'paid_cents': 57, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [623, 50]), ({'now': 1006, 'expiry': 975, 'paid_cents': 428, 'rate_per_hour': 250, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 309]), ({'now': 424, 'expiry': 372, 'paid_cents': 544, 'rate_per_hour': 250, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [609, 538]), ({'now': 1080, 'expiry': 1100, 'paid_cents': 100, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 148, 'expiry': 178, 'paid_cents': 179, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 100])], [({'now': 826, 'expiry': 909, 'paid_cents': 304, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [946, 124]), ({'now': 420, 'expiry': None, 'paid_cents': 200, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 200]), ({'now': 1080, 'expiry': None, 'paid_cents': 252, 'rate_per_hour': 100, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1080, 'expiry': 1100, 'paid_cents': 100, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 943, 'expiry': None, 'paid_cents': 503, 'rate_per_hour': 150, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 343]), ({'now': 1080, 'expiry': None, 'paid_cents': 506, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 779, 'expiry': None, 'paid_cents': 506, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [899, 300]), ({'now': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234])], [({'now': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234]), ({'now': 104, 'expiry': 123, 'paid_cents': 90, 'rate_per_hour': 250, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [501, 88]), ({'now': 1080, 'expiry': 1100, 'paid_cents': 100, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 606, 'expiry': 668, 'paid_cents': 424, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [668, 0]), ({'now': 480, 'expiry': None, 'paid_cents': 287, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [645, 275]), ({'now': 480, 'expiry': None, 'paid_cents': 3, 'rate_per_hour': 150, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [480, 0]), ({'now': 1040, 'expiry': None, 'paid_cents': 333, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 100]), ({'now': 460, 'expiry': None, 'paid_cents': 15, 'rate_per_hour': 200, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [484, 14])], [({'now': 480, 'expiry': 490, 'paid_cents': 142, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 84]), ({'now': 480, 'expiry': None, 'paid_cents': 474, 'rate_per_hour': 150, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [660, 450]), ({'now': 480, 'expiry': 538, 'paid_cents': 595, 'rate_per_hour': 250, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [680, 592]), ({'now': 1080, 'expiry': 1081, 'paid_cents': 121, 'rate_per_hour': 250, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1080, 'expiry': 1100, 'paid_cents': 100, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234]), ({'now': 480, 'expiry': 543, 'paid_cents': 144, 'rate_per_hour': 250, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [573, 125]), ({'now': 1040, 'expiry': None, 'paid_cents': 333, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 100])]]
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 fixtureActualExpectedOutcome
fee oracle 0[None, 0][None, 0]Passed
fee oracle 1[947, 391][947, 392]Failed
fee oracle 2[720, 233][720, 234]Failed
fee oracle 3[541, 208][541, 209]Failed
fee oracle 4[904, 100][904, 100]Passed
fee oracle 5[540, 200][540, 200]Passed
fee oracle 6[1120, 0][1120, 0]Passed
fee oracle 7[1080, 100][1080, 100]Passed

SHA-256 / bce033842becf4dd2099eab4727de8cd7ade5968f34615413fbc7c445bb78b4d

2 / The unsuccessful fix

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

N = 1
observations = []
def solve(x):
    inc = x['increment']
    c = x['paid_cents'] - x['paid_cents'] % inc
    now = x['now']
    if now >= x['enf_end']:
        return [None, 0]
    base = max(now, x['enf_start'])
    start = base if x['expiry'] is None else max(base, x['expiry'])
    mins = c * 60 // x['rate_per_hour']
    end = min(start + mins, base + x['max_minutes'], x['enf_end'])
    used = max(0, end - start)
    cost = min(c, c if used else 0)
    return [max(end, start), cost]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'now': 1080, 'expiry': None, 'paid_cents': 342, 'rate_per_hour': 200, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 853, 'expiry': None, 'paid_cents': 395, 'rate_per_hour': 250, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [947, 392]), ({'now': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234]), ({'now': 491, 'expiry': None, 'paid_cents': 211, 'rate_per_hour': 250, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [541, 209]), ({'now': 880, 'expiry': None, 'paid_cents': 102, 'rate_per_hour': 250, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [904, 100]), ({'now': 420, 'expiry': None, 'paid_cents': 200, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 200]), ({'now': 1048, 'expiry': 1120, 'paid_cents': 599, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1120, 0]), ({'now': 1040, 'expiry': None, 'paid_cents': 333, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 100])], [({'now': 783, 'expiry': None, 'paid_cents': 518, 'rate_per_hour': 250, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [906, 513]), ({'now': 420, 'expiry': None, 'paid_cents': 200, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 200]), ({'now': 1040, 'expiry': None, 'paid_cents': 333, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 100]), ({'now': 608, 'expiry': 560, 'paid_cents': 57, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [623, 50]), ({'now': 1006, 'expiry': 975, 'paid_cents': 428, 'rate_per_hour': 250, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 309]), ({'now': 424, 'expiry': 372, 'paid_cents': 544, 'rate_per_hour': 250, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [609, 538]), ({'now': 1080, 'expiry': 1100, 'paid_cents': 100, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 148, 'expiry': 178, 'paid_cents': 179, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 100])], [({'now': 826, 'expiry': 909, 'paid_cents': 304, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [946, 124]), ({'now': 420, 'expiry': None, 'paid_cents': 200, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 200]), ({'now': 1080, 'expiry': None, 'paid_cents': 252, 'rate_per_hour': 100, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1080, 'expiry': 1100, 'paid_cents': 100, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 943, 'expiry': None, 'paid_cents': 503, 'rate_per_hour': 150, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 343]), ({'now': 1080, 'expiry': None, 'paid_cents': 506, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 779, 'expiry': None, 'paid_cents': 506, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [899, 300]), ({'now': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234])], [({'now': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234]), ({'now': 104, 'expiry': 123, 'paid_cents': 90, 'rate_per_hour': 250, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [501, 88]), ({'now': 1080, 'expiry': 1100, 'paid_cents': 100, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 606, 'expiry': 668, 'paid_cents': 424, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [668, 0]), ({'now': 480, 'expiry': None, 'paid_cents': 287, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [645, 275]), ({'now': 480, 'expiry': None, 'paid_cents': 3, 'rate_per_hour': 150, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [480, 0]), ({'now': 1040, 'expiry': None, 'paid_cents': 333, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 100]), ({'now': 460, 'expiry': None, 'paid_cents': 15, 'rate_per_hour': 200, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [484, 14])], [({'now': 480, 'expiry': 490, 'paid_cents': 142, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 84]), ({'now': 480, 'expiry': None, 'paid_cents': 474, 'rate_per_hour': 150, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [660, 450]), ({'now': 480, 'expiry': 538, 'paid_cents': 595, 'rate_per_hour': 250, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [680, 592]), ({'now': 1080, 'expiry': 1081, 'paid_cents': 121, 'rate_per_hour': 250, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1080, 'expiry': 1100, 'paid_cents': 100, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234]), ({'now': 480, 'expiry': 543, 'paid_cents': 144, 'rate_per_hour': 250, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [573, 125]), ({'now': 1040, 'expiry': None, 'paid_cents': 333, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 100])]]
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 fixtureActualExpectedOutcome
fee oracle 0[None, 0][None, 0]Passed
fee oracle 1[947, 395][947, 392]Failed
fee oracle 2[720, 400][720, 234]Failed
fee oracle 3[541, 210][541, 209]Failed
fee oracle 4[904, 100][904, 100]Passed
fee oracle 5[540, 200][540, 200]Passed
fee oracle 6[1120, 0][1120, 0]Passed
fee oracle 7[1080, 325][1080, 100]Failed

SHA-256 / e6621d8b0557b263a44524b5fc9cd458503e42a97a12636c3ef684c50ed1dfa7

3 / The verified repair

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

N = 1
observations = []
def solve(x):
    inc = x['increment']
    c = x['paid_cents'] - x['paid_cents'] % inc
    now = x['now']
    if now >= x['enf_end']:
        return [None, 0]
    base = max(now, x['enf_start'])
    start = base if x['expiry'] is None else max(base, x['expiry'])
    mins = c * 60 // x['rate_per_hour']
    end = min(start + mins, base + x['max_minutes'], x['enf_end'])
    used = max(0, end - start)
    cost = min(c, -(-used * x['rate_per_hour'] // 60))
    return [max(end, start), cost]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'now': 1080, 'expiry': None, 'paid_cents': 342, 'rate_per_hour': 200, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 853, 'expiry': None, 'paid_cents': 395, 'rate_per_hour': 250, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [947, 392]), ({'now': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234]), ({'now': 491, 'expiry': None, 'paid_cents': 211, 'rate_per_hour': 250, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [541, 209]), ({'now': 880, 'expiry': None, 'paid_cents': 102, 'rate_per_hour': 250, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [904, 100]), ({'now': 420, 'expiry': None, 'paid_cents': 200, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 200]), ({'now': 1048, 'expiry': 1120, 'paid_cents': 599, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1120, 0]), ({'now': 1040, 'expiry': None, 'paid_cents': 333, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 100])], [({'now': 783, 'expiry': None, 'paid_cents': 518, 'rate_per_hour': 250, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [906, 513]), ({'now': 420, 'expiry': None, 'paid_cents': 200, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 200]), ({'now': 1040, 'expiry': None, 'paid_cents': 333, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 100]), ({'now': 608, 'expiry': 560, 'paid_cents': 57, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [623, 50]), ({'now': 1006, 'expiry': 975, 'paid_cents': 428, 'rate_per_hour': 250, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 309]), ({'now': 424, 'expiry': 372, 'paid_cents': 544, 'rate_per_hour': 250, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [609, 538]), ({'now': 1080, 'expiry': 1100, 'paid_cents': 100, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 148, 'expiry': 178, 'paid_cents': 179, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 100])], [({'now': 826, 'expiry': 909, 'paid_cents': 304, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [946, 124]), ({'now': 420, 'expiry': None, 'paid_cents': 200, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 200]), ({'now': 1080, 'expiry': None, 'paid_cents': 252, 'rate_per_hour': 100, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1080, 'expiry': 1100, 'paid_cents': 100, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 943, 'expiry': None, 'paid_cents': 503, 'rate_per_hour': 150, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 343]), ({'now': 1080, 'expiry': None, 'paid_cents': 506, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 779, 'expiry': None, 'paid_cents': 506, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [899, 300]), ({'now': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234])], [({'now': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234]), ({'now': 104, 'expiry': 123, 'paid_cents': 90, 'rate_per_hour': 250, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [501, 88]), ({'now': 1080, 'expiry': 1100, 'paid_cents': 100, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 606, 'expiry': 668, 'paid_cents': 424, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [668, 0]), ({'now': 480, 'expiry': None, 'paid_cents': 287, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [645, 275]), ({'now': 480, 'expiry': None, 'paid_cents': 3, 'rate_per_hour': 150, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [480, 0]), ({'now': 1040, 'expiry': None, 'paid_cents': 333, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 100]), ({'now': 460, 'expiry': None, 'paid_cents': 15, 'rate_per_hour': 200, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [484, 14])], [({'now': 480, 'expiry': 490, 'paid_cents': 142, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 84]), ({'now': 480, 'expiry': None, 'paid_cents': 474, 'rate_per_hour': 150, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [660, 450]), ({'now': 480, 'expiry': 538, 'paid_cents': 595, 'rate_per_hour': 250, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [680, 592]), ({'now': 1080, 'expiry': 1081, 'paid_cents': 121, 'rate_per_hour': 250, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1080, 'expiry': 1100, 'paid_cents': 100, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234]), ({'now': 480, 'expiry': 543, 'paid_cents': 144, 'rate_per_hour': 250, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [573, 125]), ({'now': 1040, 'expiry': None, 'paid_cents': 333, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 100])]]
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 fixtureActualExpectedOutcome
fee oracle 0[None, 0][None, 0]Passed
fee oracle 1[947, 392][947, 392]Passed
fee oracle 2[720, 234][720, 234]Passed
fee oracle 3[541, 209][541, 209]Passed
fee oracle 4[904, 100][904, 100]Passed
fee oracle 5[540, 200][540, 200]Passed
fee oracle 6[1120, 0][1120, 0]Passed
fee oracle 7[1080, 100][1080, 100]Passed

SHA-256 / b77687ad2357bca217e10bc4a2de9d4b4c652520e435ca936f63f0ffe4e5f156

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 2026-09-29T14:48:02.526693+00:00.

Case digest / 10094265be123a38b2c2506f392eaf32a8d6d9305ad61459a0cfa77380987e0a