FA-68406 / Toll and parking fee computation / Open access

Early bird flat rate: overnight stays qualify for the early bird · case 01

Early bird flat rate returns a wrong result when overnight stays qualify for the early bird.

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

ROOT CAUSE

Any later exit day qualifies, so multi-day stays pay a single early bird rate.

VERIFIED REPAIR

Restore the same-day exit rule so that the step reads `xd == ed`.

Unsuccessful approach: Allowing next-day exits still grants the flat rate to overnight stays.

Case contract

Input {entry: [day, minute], exit: [day, minute], hourly, daily_max, early}; day % 7 == 0 is Monday. Regular fee = min(started hours*hourly, started 24h periods (at least 1)*daily_max). Early bird applies on weekdays when entry is 06:00-09:00 inclusive and exit is the same day 15:00-19:00 inclusive; the customer pays min(regular, early). Negative durations are 'invalid'.

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):
    ed, em = x['entry']
    xd, xm = x['exit']
    dur = (xd - ed) * 1440 + xm - em
    if dur < 0:
        return 'invalid'
    hours = -(-dur // 60)
    days = max(1, -(-dur // 1440))
    regular = min(hours * x['hourly'], days * x['daily_max'])
    eligible = ed % 7 < 5 and 360 <= em <= 540 and xd >= ed and 900 <= xm <= 1140
    if eligible:
        return min(regular, x['early'])
    return regular
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'entry': [1, 360], 'exit': [1, 1140], 'hourly': 400, 'daily_max': 1800, 'early': 1000}, 1000), ({'entry': [1, 360], 'exit': [2, 1140], 'hourly': 300, 'daily_max': 1200, 'early': 1000}, 2400), ({'entry': [1, 0], 'exit': [2, 0], 'hourly': 300, 'daily_max': 1800, 'early': 1000}, 1800), ({'entry': [10, 540], 'exit': [10, 900], 'hourly': 200, 'daily_max': 1800, 'early': 1400}, 1200), ({'entry': [2, 360], 'exit': [4, 1075], 'hourly': 300, 'daily_max': 1200, 'early': 900}, 3600), ({'entry': [0, 480], 'exit': [0, 1300], 'hourly': 300, 'daily_max': 2500, 'early': 1000}, 2500), ({'entry': [11, 360], 'exit': [13, 900], 'hourly': 400, 'daily_max': 2500, 'early': 1000}, 7500), ({'entry': [2, 540], 'exit': [3, 1140], 'hourly': 200, 'daily_max': 1200, 'early': 1400}, 2400)], [({'entry': [2, 540], 'exit': [2, 1000], 'hourly': 300, 'daily_max': 2500, 'early': 1000}, 1000), ({'entry': [3, 539], 'exit': [4, 996], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [13, 541], 'exit': [13, 900], 'hourly': 300, 'daily_max': 2500, 'early': 900}, 1800), ({'entry': [0, 359], 'exit': [2, 900], 'hourly': 300, 'daily_max': 2500, 'early': 1000}, 7500), ({'entry': [3, 400], 'exit': [3, 1000], 'hourly': 300, 'daily_max': 800, 'early': 1000}, 800), ({'entry': [3, 540], 'exit': [3, 915], 'hourly': 200, 'daily_max': 1200, 'early': 1400}, 1200), ({'entry': [3, 420], 'exit': [4, 960], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [8, 540], 'exit': [10, 1078], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 5400)], [({'entry': [6, 540], 'exit': [6, 900], 'hourly': 200, 'daily_max': 1800, 'early': 1000}, 1200), ({'entry': [3, 400], 'exit': [3, 1000], 'hourly': 300, 'daily_max': 800, 'early': 1000}, 800), ({'entry': [13, 360], 'exit': [13, 899], 'hourly': 200, 'daily_max': 1800, 'early': 900}, 1800), ({'entry': [7, 360], 'exit': [9, 900], 'hourly': 200, 'daily_max': 1800, 'early': 900}, 5400), ({'entry': [9, 540], 'exit': [10, 900], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [3, 420], 'exit': [4, 960], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [0, 480], 'exit': [0, 1300], 'hourly': 300, 'daily_max': 2500, 'early': 1000}, 2500), ({'entry': [12, 360], 'exit': [12, 899], 'hourly': 400, 'daily_max': 2500, 'early': 1400}, 2500)], [({'entry': [9, 540], 'exit': [11, 1140], 'hourly': 200, 'daily_max': 1200, 'early': 1000}, 3600), ({'entry': [3, 359], 'exit': [3, 1141], 'hourly': 200, 'daily_max': 2500, 'early': 1000}, 2500), ({'entry': [3, 540], 'exit': [4, 1140], 'hourly': 200, 'daily_max': 1800, 'early': 1400}, 3600), ({'entry': [3, 400], 'exit': [3, 1000], 'hourly': 300, 'daily_max': 800, 'early': 1000}, 800), ({'entry': [6, 1384], 'exit': [6, 1439], 'hourly': 300, 'daily_max': 1800, 'early': 1400}, 300), ({'entry': [2, 248], 'exit': [3, 843], 'hourly': 200, 'daily_max': 1200, 'early': 1000}, 2400), ({'entry': [3, 420], 'exit': [4, 960], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [1, 0], 'exit': [2, 0], 'hourly': 300, 'daily_max': 1800, 'early': 1000}, 1800)], [({'entry': [11, 401], 'exit': [11, 991], 'hourly': 400, 'daily_max': 2500, 'early': 900}, 900), ({'entry': [2, 540], 'exit': [4, 1140], 'hourly': 200, 'daily_max': 1800, 'early': 900}, 5400), ({'entry': [1, 0], 'exit': [2, 0], 'hourly': 300, 'daily_max': 1800, 'early': 1000}, 1800), ({'entry': [11, 540], 'exit': [12, 1140], 'hourly': 300, 'daily_max': 1200, 'early': 900}, 2400), ({'entry': [13, 359], 'exit': [14, 1141], 'hourly': 300, 'daily_max': 2500, 'early': 900}, 5000), ({'entry': [3, 400], 'exit': [3, 1000], 'hourly': 300, 'daily_max': 800, 'early': 1000}, 800), ({'entry': [3, 420], 'exit': [4, 960], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [11, 360], 'exit': [11, 900], 'hourly': 300, 'daily_max': 2500, 'early': 1400}, 1400)]]
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	`1000`	`1000`	Passed
fee oracle 1	`1000`	`2400`	Failed
fee oracle 2	`1800`	`1800`	Passed
fee oracle 3	`1200`	`1200`	Passed
fee oracle 4	`900`	`3600`	Failed
fee oracle 5	`2500`	`2500`	Passed
fee oracle 6	`1000`	`7500`	Failed
fee oracle 7	`1400`	`2400`	Failed

SHA-256 / a76e64571cf74b0edeacc9827f2d9f6d88aec58460bb284ab2326e531ed17c98

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(x):
    ed, em = x['entry']
    xd, xm = x['exit']
    dur = (xd - ed) * 1440 + xm - em
    if dur < 0:
        return 'invalid'
    hours = -(-dur // 60)
    days = max(1, -(-dur // 1440))
    regular = min(hours * x['hourly'], days * x['daily_max'])
    eligible = ed % 7 < 5 and 360 <= em <= 540 and xd - ed <= 1 and 900 <= xm <= 1140
    if eligible:
        return min(regular, x['early'])
    return regular
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'entry': [1, 360], 'exit': [1, 1140], 'hourly': 400, 'daily_max': 1800, 'early': 1000}, 1000), ({'entry': [1, 360], 'exit': [2, 1140], 'hourly': 300, 'daily_max': 1200, 'early': 1000}, 2400), ({'entry': [1, 0], 'exit': [2, 0], 'hourly': 300, 'daily_max': 1800, 'early': 1000}, 1800), ({'entry': [10, 540], 'exit': [10, 900], 'hourly': 200, 'daily_max': 1800, 'early': 1400}, 1200), ({'entry': [2, 360], 'exit': [4, 1075], 'hourly': 300, 'daily_max': 1200, 'early': 900}, 3600), ({'entry': [0, 480], 'exit': [0, 1300], 'hourly': 300, 'daily_max': 2500, 'early': 1000}, 2500), ({'entry': [11, 360], 'exit': [13, 900], 'hourly': 400, 'daily_max': 2500, 'early': 1000}, 7500), ({'entry': [2, 540], 'exit': [3, 1140], 'hourly': 200, 'daily_max': 1200, 'early': 1400}, 2400)], [({'entry': [2, 540], 'exit': [2, 1000], 'hourly': 300, 'daily_max': 2500, 'early': 1000}, 1000), ({'entry': [3, 539], 'exit': [4, 996], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [13, 541], 'exit': [13, 900], 'hourly': 300, 'daily_max': 2500, 'early': 900}, 1800), ({'entry': [0, 359], 'exit': [2, 900], 'hourly': 300, 'daily_max': 2500, 'early': 1000}, 7500), ({'entry': [3, 400], 'exit': [3, 1000], 'hourly': 300, 'daily_max': 800, 'early': 1000}, 800), ({'entry': [3, 540], 'exit': [3, 915], 'hourly': 200, 'daily_max': 1200, 'early': 1400}, 1200), ({'entry': [3, 420], 'exit': [4, 960], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [8, 540], 'exit': [10, 1078], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 5400)], [({'entry': [6, 540], 'exit': [6, 900], 'hourly': 200, 'daily_max': 1800, 'early': 1000}, 1200), ({'entry': [3, 400], 'exit': [3, 1000], 'hourly': 300, 'daily_max': 800, 'early': 1000}, 800), ({'entry': [13, 360], 'exit': [13, 899], 'hourly': 200, 'daily_max': 1800, 'early': 900}, 1800), ({'entry': [7, 360], 'exit': [9, 900], 'hourly': 200, 'daily_max': 1800, 'early': 900}, 5400), ({'entry': [9, 540], 'exit': [10, 900], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [3, 420], 'exit': [4, 960], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [0, 480], 'exit': [0, 1300], 'hourly': 300, 'daily_max': 2500, 'early': 1000}, 2500), ({'entry': [12, 360], 'exit': [12, 899], 'hourly': 400, 'daily_max': 2500, 'early': 1400}, 2500)], [({'entry': [9, 540], 'exit': [11, 1140], 'hourly': 200, 'daily_max': 1200, 'early': 1000}, 3600), ({'entry': [3, 359], 'exit': [3, 1141], 'hourly': 200, 'daily_max': 2500, 'early': 1000}, 2500), ({'entry': [3, 540], 'exit': [4, 1140], 'hourly': 200, 'daily_max': 1800, 'early': 1400}, 3600), ({'entry': [3, 400], 'exit': [3, 1000], 'hourly': 300, 'daily_max': 800, 'early': 1000}, 800), ({'entry': [6, 1384], 'exit': [6, 1439], 'hourly': 300, 'daily_max': 1800, 'early': 1400}, 300), ({'entry': [2, 248], 'exit': [3, 843], 'hourly': 200, 'daily_max': 1200, 'early': 1000}, 2400), ({'entry': [3, 420], 'exit': [4, 960], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [1, 0], 'exit': [2, 0], 'hourly': 300, 'daily_max': 1800, 'early': 1000}, 1800)], [({'entry': [11, 401], 'exit': [11, 991], 'hourly': 400, 'daily_max': 2500, 'early': 900}, 900), ({'entry': [2, 540], 'exit': [4, 1140], 'hourly': 200, 'daily_max': 1800, 'early': 900}, 5400), ({'entry': [1, 0], 'exit': [2, 0], 'hourly': 300, 'daily_max': 1800, 'early': 1000}, 1800), ({'entry': [11, 540], 'exit': [12, 1140], 'hourly': 300, 'daily_max': 1200, 'early': 900}, 2400), ({'entry': [13, 359], 'exit': [14, 1141], 'hourly': 300, 'daily_max': 2500, 'early': 900}, 5000), ({'entry': [3, 400], 'exit': [3, 1000], 'hourly': 300, 'daily_max': 800, 'early': 1000}, 800), ({'entry': [3, 420], 'exit': [4, 960], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [11, 360], 'exit': [11, 900], 'hourly': 300, 'daily_max': 2500, 'early': 1400}, 1400)]]
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	`1000`	`1000`	Passed
fee oracle 1	`1000`	`2400`	Failed
fee oracle 2	`1800`	`1800`	Passed
fee oracle 3	`1200`	`1200`	Passed
fee oracle 4	`3600`	`3600`	Passed
fee oracle 5	`2500`	`2500`	Passed
fee oracle 6	`7500`	`7500`	Passed
fee oracle 7	`1400`	`2400`	Failed

SHA-256 / 0724697c814a15aa3bb4b2d09bdd7636f66e057d690a60e6d66796f40076e5b4

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(x):
    ed, em = x['entry']
    xd, xm = x['exit']
    dur = (xd - ed) * 1440 + xm - em
    if dur < 0:
        return 'invalid'
    hours = -(-dur // 60)
    days = max(1, -(-dur // 1440))
    regular = min(hours * x['hourly'], days * x['daily_max'])
    eligible = ed % 7 < 5 and 360 <= em <= 540 and xd == ed and 900 <= xm <= 1140
    if eligible:
        return min(regular, x['early'])
    return regular
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[({'entry': [1, 360], 'exit': [1, 1140], 'hourly': 400, 'daily_max': 1800, 'early': 1000}, 1000), ({'entry': [1, 360], 'exit': [2, 1140], 'hourly': 300, 'daily_max': 1200, 'early': 1000}, 2400), ({'entry': [1, 0], 'exit': [2, 0], 'hourly': 300, 'daily_max': 1800, 'early': 1000}, 1800), ({'entry': [10, 540], 'exit': [10, 900], 'hourly': 200, 'daily_max': 1800, 'early': 1400}, 1200), ({'entry': [2, 360], 'exit': [4, 1075], 'hourly': 300, 'daily_max': 1200, 'early': 900}, 3600), ({'entry': [0, 480], 'exit': [0, 1300], 'hourly': 300, 'daily_max': 2500, 'early': 1000}, 2500), ({'entry': [11, 360], 'exit': [13, 900], 'hourly': 400, 'daily_max': 2500, 'early': 1000}, 7500), ({'entry': [2, 540], 'exit': [3, 1140], 'hourly': 200, 'daily_max': 1200, 'early': 1400}, 2400)], [({'entry': [2, 540], 'exit': [2, 1000], 'hourly': 300, 'daily_max': 2500, 'early': 1000}, 1000), ({'entry': [3, 539], 'exit': [4, 996], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [13, 541], 'exit': [13, 900], 'hourly': 300, 'daily_max': 2500, 'early': 900}, 1800), ({'entry': [0, 359], 'exit': [2, 900], 'hourly': 300, 'daily_max': 2500, 'early': 1000}, 7500), ({'entry': [3, 400], 'exit': [3, 1000], 'hourly': 300, 'daily_max': 800, 'early': 1000}, 800), ({'entry': [3, 540], 'exit': [3, 915], 'hourly': 200, 'daily_max': 1200, 'early': 1400}, 1200), ({'entry': [3, 420], 'exit': [4, 960], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [8, 540], 'exit': [10, 1078], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 5400)], [({'entry': [6, 540], 'exit': [6, 900], 'hourly': 200, 'daily_max': 1800, 'early': 1000}, 1200), ({'entry': [3, 400], 'exit': [3, 1000], 'hourly': 300, 'daily_max': 800, 'early': 1000}, 800), ({'entry': [13, 360], 'exit': [13, 899], 'hourly': 200, 'daily_max': 1800, 'early': 900}, 1800), ({'entry': [7, 360], 'exit': [9, 900], 'hourly': 200, 'daily_max': 1800, 'early': 900}, 5400), ({'entry': [9, 540], 'exit': [10, 900], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [3, 420], 'exit': [4, 960], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [0, 480], 'exit': [0, 1300], 'hourly': 300, 'daily_max': 2500, 'early': 1000}, 2500), ({'entry': [12, 360], 'exit': [12, 899], 'hourly': 400, 'daily_max': 2500, 'early': 1400}, 2500)], [({'entry': [9, 540], 'exit': [11, 1140], 'hourly': 200, 'daily_max': 1200, 'early': 1000}, 3600), ({'entry': [3, 359], 'exit': [3, 1141], 'hourly': 200, 'daily_max': 2500, 'early': 1000}, 2500), ({'entry': [3, 540], 'exit': [4, 1140], 'hourly': 200, 'daily_max': 1800, 'early': 1400}, 3600), ({'entry': [3, 400], 'exit': [3, 1000], 'hourly': 300, 'daily_max': 800, 'early': 1000}, 800), ({'entry': [6, 1384], 'exit': [6, 1439], 'hourly': 300, 'daily_max': 1800, 'early': 1400}, 300), ({'entry': [2, 248], 'exit': [3, 843], 'hourly': 200, 'daily_max': 1200, 'early': 1000}, 2400), ({'entry': [3, 420], 'exit': [4, 960], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [1, 0], 'exit': [2, 0], 'hourly': 300, 'daily_max': 1800, 'early': 1000}, 1800)], [({'entry': [11, 401], 'exit': [11, 991], 'hourly': 400, 'daily_max': 2500, 'early': 900}, 900), ({'entry': [2, 540], 'exit': [4, 1140], 'hourly': 200, 'daily_max': 1800, 'early': 900}, 5400), ({'entry': [1, 0], 'exit': [2, 0], 'hourly': 300, 'daily_max': 1800, 'early': 1000}, 1800), ({'entry': [11, 540], 'exit': [12, 1140], 'hourly': 300, 'daily_max': 1200, 'early': 900}, 2400), ({'entry': [13, 359], 'exit': [14, 1141], 'hourly': 300, 'daily_max': 2500, 'early': 900}, 5000), ({'entry': [3, 400], 'exit': [3, 1000], 'hourly': 300, 'daily_max': 800, 'early': 1000}, 800), ({'entry': [3, 420], 'exit': [4, 960], 'hourly': 300, 'daily_max': 1800, 'early': 900}, 3600), ({'entry': [11, 360], 'exit': [11, 900], 'hourly': 300, 'daily_max': 2500, 'early': 1400}, 1400)]]
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	`1000`	`1000`	Passed
fee oracle 1	`2400`	`2400`	Passed
fee oracle 2	`1800`	`1800`	Passed
fee oracle 3	`1200`	`1200`	Passed
fee oracle 4	`3600`	`3600`	Passed
fee oracle 5	`2500`	`2500`	Passed
fee oracle 6	`7500`	`7500`	Passed
fee oracle 7	`2400`	`2400`	Passed

SHA-256 / 67b68104cc83c2f5418cfa9f2cbb9f92c79d31de999ea698f1fe0538c25b0f6f

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 2026-09-29T14:48:01.892245+00:00.

Case digest / 0819d5fdb02cd69c9ea00d5acd3d2b6af33daa752f0a1c0e7ca371410fb793f1