FAILURE MAP
← Case archive

FA-68481 / Toll and parking fee computation / Open access

Street meter time purchase: a purchase at exactly enforcement end is processed · case 01

Street meter time purchase returns a wrong result when a purchase at exactly enforcement end is processed.

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

ROOT CAUSE

At the enforcement end minute the meter still returns an expiry instead of rejecting payment.

VERIFIED REPAIR

Restore the after-hours rejection rule so that the step reads `if now >= x['enf_end']:`.

Unsuccessful approach: Only rejecting when no time is on the meter still processes after-hours top-ups.

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': 1078, 'paid_cents': 85, 'rate_per_hour': 100, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 1080, 'expiry': None, 'paid_cents': 480, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [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': 1040, 'expiry': None, 'paid_cents': 333, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 100]), ({'now': 1350, 'expiry': 1335, 'paid_cents': 5, 'rate_per_hour': 250, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1080, 'expiry': 1071, 'paid_cents': 491, 'rate_per_hour': 250, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'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': 1243, 'expiry': 1214, 'paid_cents': 292, 'rate_per_hour': 200, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0])], [({'now': 1080, 'expiry': 1152, 'paid_cents': 523, 'rate_per_hour': 150, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'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': 233, 'expiry': 231, 'paid_cents': 298, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 100]), ({'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': 1080, 'expiry': 1025, 'paid_cents': 393, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 655, 'expiry': None, 'paid_cents': 200, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [735, 200]), ({'now': 1069, 'expiry': 1154, 'paid_cents': 524, 'rate_per_hour': 150, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [1154, 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': 1080, 'expiry': 1100, 'paid_cents': 100, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 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': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234]), ({'now': 1080, 'expiry': None, 'paid_cents': 109, 'rate_per_hour': 100, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1221, 'expiry': 1229, 'paid_cents': 328, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1208, 'expiry': None, 'paid_cents': 533, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 1080, 'expiry': 1154, 'paid_cents': 297, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 480, 'expiry': None, 'paid_cents': 226, 'rate_per_hour': 100, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [600, 200])], [({'now': 1080, 'expiry': 1168, 'paid_cents': 356, 'rate_per_hour': 200, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1080, 'expiry': None, 'paid_cents': 584, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 1080, 'expiry': None, 'paid_cents': 350, 'rate_per_hour': 200, 'max_minutes': 60, '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': None, 'paid_cents': 469, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [600, 400]), ({'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': 1087, 'expiry': 1093, 'paid_cents': 264, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'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': 63, 'expiry': 65, 'paid_cents': 478, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [600, 400]), ({'now': 1080, 'expiry': 1106, 'paid_cents': 493, 'rate_per_hour': 150, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 480, 'expiry': 511, 'paid_cents': 308, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [600, 297]), ({'now': 1080, 'expiry': 1112, 'paid_cents': 319, 'rate_per_hour': 200, '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': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234]), ({'now': 655, 'expiry': None, 'paid_cents': 248, 'rate_per_hour': 200, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [715, 200])]]
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[1080, 0][None, 0]Failed
fee oracle 1[1080, 0][None, 0]Failed
fee oracle 2[720, 234][720, 234]Passed
fee oracle 3[1080, 100][1080, 100]Passed
fee oracle 4[None, 0][None, 0]Passed
fee oracle 5[1080, 0][None, 0]Failed
fee oracle 6[540, 200][540, 200]Passed
fee oracle 7[None, 0][None, 0]Passed

SHA-256 / a0d2a88429f86a0480f549741b26768aa8ceea144f778d5dedcb940f67dd0614

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'] and x['expiry'] is None:
        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': 1078, 'paid_cents': 85, 'rate_per_hour': 100, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 1080, 'expiry': None, 'paid_cents': 480, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [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': 1040, 'expiry': None, 'paid_cents': 333, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 100]), ({'now': 1350, 'expiry': 1335, 'paid_cents': 5, 'rate_per_hour': 250, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1080, 'expiry': 1071, 'paid_cents': 491, 'rate_per_hour': 250, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'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': 1243, 'expiry': 1214, 'paid_cents': 292, 'rate_per_hour': 200, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0])], [({'now': 1080, 'expiry': 1152, 'paid_cents': 523, 'rate_per_hour': 150, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'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': 233, 'expiry': 231, 'paid_cents': 298, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 100]), ({'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': 1080, 'expiry': 1025, 'paid_cents': 393, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 655, 'expiry': None, 'paid_cents': 200, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [735, 200]), ({'now': 1069, 'expiry': 1154, 'paid_cents': 524, 'rate_per_hour': 150, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [1154, 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': 1080, 'expiry': 1100, 'paid_cents': 100, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 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': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234]), ({'now': 1080, 'expiry': None, 'paid_cents': 109, 'rate_per_hour': 100, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1221, 'expiry': 1229, 'paid_cents': 328, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1208, 'expiry': None, 'paid_cents': 533, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 1080, 'expiry': 1154, 'paid_cents': 297, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 480, 'expiry': None, 'paid_cents': 226, 'rate_per_hour': 100, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [600, 200])], [({'now': 1080, 'expiry': 1168, 'paid_cents': 356, 'rate_per_hour': 200, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1080, 'expiry': None, 'paid_cents': 584, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 1080, 'expiry': None, 'paid_cents': 350, 'rate_per_hour': 200, 'max_minutes': 60, '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': None, 'paid_cents': 469, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [600, 400]), ({'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': 1087, 'expiry': 1093, 'paid_cents': 264, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'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': 63, 'expiry': 65, 'paid_cents': 478, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [600, 400]), ({'now': 1080, 'expiry': 1106, 'paid_cents': 493, 'rate_per_hour': 150, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 480, 'expiry': 511, 'paid_cents': 308, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [600, 297]), ({'now': 1080, 'expiry': 1112, 'paid_cents': 319, 'rate_per_hour': 200, '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': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234]), ({'now': 655, 'expiry': None, 'paid_cents': 248, 'rate_per_hour': 200, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [715, 200])]]
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[1080, 0][None, 0]Failed
fee oracle 1[None, 0][None, 0]Passed
fee oracle 2[720, 234][720, 234]Passed
fee oracle 3[1080, 100][1080, 100]Passed
fee oracle 4[1350, 0][None, 0]Failed
fee oracle 5[1080, 0][None, 0]Failed
fee oracle 6[540, 200][540, 200]Passed
fee oracle 7[1243, 0][None, 0]Failed

SHA-256 / 80b6d11a54f4f8f78d941ad1ae8517754cad2aea74a9fc139f6ac31d86a63e77

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': 1078, 'paid_cents': 85, 'rate_per_hour': 100, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 1080, 'expiry': None, 'paid_cents': 480, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [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': 1040, 'expiry': None, 'paid_cents': 333, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [1080, 100]), ({'now': 1350, 'expiry': 1335, 'paid_cents': 5, 'rate_per_hour': 250, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1080, 'expiry': 1071, 'paid_cents': 491, 'rate_per_hour': 250, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'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': 1243, 'expiry': 1214, 'paid_cents': 292, 'rate_per_hour': 200, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0])], [({'now': 1080, 'expiry': 1152, 'paid_cents': 523, 'rate_per_hour': 150, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'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': 233, 'expiry': 231, 'paid_cents': 298, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [540, 100]), ({'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': 1080, 'expiry': 1025, 'paid_cents': 393, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 655, 'expiry': None, 'paid_cents': 200, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [735, 200]), ({'now': 1069, 'expiry': 1154, 'paid_cents': 524, 'rate_per_hour': 150, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [1154, 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': 1080, 'expiry': 1100, 'paid_cents': 100, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 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': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234]), ({'now': 1080, 'expiry': None, 'paid_cents': 109, 'rate_per_hour': 100, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1221, 'expiry': 1229, 'paid_cents': 328, 'rate_per_hour': 150, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1208, 'expiry': None, 'paid_cents': 533, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 1080, 'expiry': 1154, 'paid_cents': 297, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 480, 'expiry': None, 'paid_cents': 226, 'rate_per_hour': 100, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [600, 200])], [({'now': 1080, 'expiry': 1168, 'paid_cents': 356, 'rate_per_hour': 200, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 1080, 'expiry': None, 'paid_cents': 584, 'rate_per_hour': 100, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'now': 1080, 'expiry': None, 'paid_cents': 350, 'rate_per_hour': 200, 'max_minutes': 60, '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': None, 'paid_cents': 469, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [600, 400]), ({'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': 1087, 'expiry': 1093, 'paid_cents': 264, 'rate_per_hour': 100, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [None, 0]), ({'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': 63, 'expiry': 65, 'paid_cents': 478, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [600, 400]), ({'now': 1080, 'expiry': 1106, 'paid_cents': 493, 'rate_per_hour': 150, 'max_minutes': 240, 'enf_start': 480, 'enf_end': 1080, 'increment': 25}, [None, 0]), ({'now': 480, 'expiry': 511, 'paid_cents': 308, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [600, 297]), ({'now': 1080, 'expiry': 1112, 'paid_cents': 319, 'rate_per_hour': 200, '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': 600, 'expiry': 650, 'paid_cents': 400, 'rate_per_hour': 200, 'max_minutes': 120, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [720, 234]), ({'now': 655, 'expiry': None, 'paid_cents': 248, 'rate_per_hour': 200, 'max_minutes': 60, 'enf_start': 480, 'enf_end': 1080, 'increment': 5}, [715, 200])]]
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[None, 0][None, 0]Passed
fee oracle 2[720, 234][720, 234]Passed
fee oracle 3[1080, 100][1080, 100]Passed
fee oracle 4[None, 0][None, 0]Passed
fee oracle 5[None, 0][None, 0]Passed
fee oracle 6[540, 200][540, 200]Passed
fee oracle 7[None, 0][None, 0]Passed

SHA-256 / 29e8cded130773b197182cea14283e35c7eb50c04d10f53e776fce767947de08

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 2026-09-29T14:48:02.523658+00:00.

Case digest / fc738f18d2966523441e48ea5ae7a71010157afdb011e5460ef9c6ef0866436a