FA-66451 / Airline fare rule evaluation / Open access

Higher-of penalty charges the lower amount · case 01

Cheap tickets are charged a tiny percentage fee instead of the minimum flat fee.

Verified by executionVariant 1 · 10 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The HIGHER rule takes the minimum of the flat and percentage fees.

THE FAILURE

The HIGHER rule takes the minimum of the flat and percentage fees.

Unsuccessful approach: Summing both components overcharges every change.

Case contract

Input {'paid','new_fare','fee','fee_pct','fee_rule' FLAT|HIGHER,'residual' CREDIT|FORFEIT,'waiver_h','hours_since_ticket'}. Fee waived when hours_since_ticket <= waiver_h; FLAT fee = fee; HIGHER = max(fee, fee_pct% of the original paid fare). Collect = max(0, new-paid) + fee; residual credit = max(0, paid-new) only when residual is CREDIT (the fee is never netted against credit). Return [collect, credit] rounded 2.

Why this case matters

Voluntary change pricing combines a fare difference, a penalty with a higher-of rule, a free-change window and residual value handling.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(x):
    paid, new = x['paid'], x['new_fare']
    if x['hours_since_ticket'] <= x['waiver_h']:
        fee = 0.0
    elif x['fee_rule'] == 'FLAT':
        fee = x['fee']
    else:
        fee = min(x['fee'], x['fee_pct'] * paid / 100)
    collect = max(0.0, new - paid) + fee
    credit = max(0.0, paid - new) if x['residual'] == 'CREDIT' else 0.0
    return [round(collect, 2), round(credit, 2)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['upgrade HIGHER rule', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 900.0, 'new_fare': 1101.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 100}, [291.0, 0.0]], ['downgrade with credit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 450.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 51}, [75.0, 150.0]], ['downgrade forfeit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 421.0, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'hours_since_ticket': 72}, [75.0, 0.0]], ['exactly 24h after ticketing', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 520.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 24}, [20.0, 0.0]], ['cheap fare minimum fee', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 310.0, 'new_fare': 310.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 30}, [75.0, 0.0]], ['pct fee exceeds flat', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 1500.0, 'new_fare': 1200.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 200}, [150.0, 300.0]], ['fee larger than residual', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 460.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 48}, [75.0, 40.0]], ['sampled case 1', {'paid': 945.21, 'new_fare': 746.1, 'fee': 50.0, 'fee_pct': 15, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 397}, [141.78, 0.0]], ['sampled case 2', {'paid': 616.49, 'new_fare': 852.38, 'fee': 150.0, 'fee_pct': 10, 'fee_rule': 'FLAT', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 48}, [385.89, 0.0]], ['sampled case 3', {'paid': 832.44, 'new_fare': 589.1, 'fee': 50.0, 'fee_pct': 15, 'fee_rule': 'FLAT', 'residual': 'FORFEIT', 'waiver_h': 48, 'hours_since_ticket': 24}, [0.0, 0.0]]], [['upgrade HIGHER rule', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 900.0, 'new_fare': 1102.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 100}, [292.0, 0.0]], ['downgrade with credit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 450.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 52}, [75.0, 150.0]], ['downgrade forfeit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 422.0, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'hours_since_ticket': 72}, [75.0, 0.0]], ['exactly 24h after ticketing', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 520.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 24}, [20.0, 0.0]], ['cheap fare minimum fee', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 320.0, 'new_fare': 310.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 30}, [75.0, 10.0]], ['pct fee exceeds flat', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 1500.0, 'new_fare': 1200.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 200}, [150.0, 300.0]], ['fee larger than residual', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 460.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 48}, [75.0, 40.0]], ['sampled case 1', {'paid': 187.06, 'new_fare': 196.65, 'fee': 150.0, 'fee_pct': 15, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 24}, [9.59, 0.0]], ['sampled case 2', {'paid': 1518.15, 'new_fare': 1549.03, 'fee': 150.0, 'fee_pct': 20, 'fee_rule': 'FLAT', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 24}, [30.88, 0.0]], ['sampled case 3', {'paid': 1212.02, 'new_fare': 1432.47, 'fee': 100.0, 'fee_pct': 5, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 48, 'hours_since_ticket': 49}, [320.45, 0.0]]], [['upgrade HIGHER rule', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 900.0, 'new_fare': 1103.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 100}, [293.0, 0.0]], ['downgrade with credit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 450.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 53}, [75.0, 150.0]], ['downgrade forfeit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 423.0, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'hours_since_ticket': 72}, [75.0, 0.0]], ['exactly 24h after ticketing', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 520.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 24}, [20.0, 0.0]], ['cheap fare minimum fee', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 330.0, 'new_fare': 310.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 30}, [75.0, 20.0]], ['pct fee exceeds flat', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 1500.0, 'new_fare': 1200.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 200}, [150.0, 300.0]], ['fee larger than residual', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 460.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 48}, [75.0, 40.0]], ['sampled case 1', {'paid': 1440.92, 'new_fare': 1296.99, 'fee': 75.0, 'fee_pct': 20, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'waiver_h': 48, 'hours_since_ticket': 24}, [0.0, 143.93]], ['sampled case 2', {'paid': 1622.18, 'new_fare': 873.9, 'fee': 150.0, 'fee_pct': 15, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 48}, [243.33, 0.0]], ['sampled case 3', {'paid': 1642.66, 'new_fare': 1568.49, 'fee': 75.0, 'fee_pct': 20, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 48, 'hours_since_ticket': 48}, [0.0, 0.0]]], [['upgrade HIGHER rule', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 900.0, 'new_fare': 1104.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 100}, [294.0, 0.0]], ['downgrade with credit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 450.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 54}, [75.0, 150.0]], ['downgrade forfeit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 424.0, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'hours_since_ticket': 72}, [75.0, 0.0]], ['exactly 24h after ticketing', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 520.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 24}, [20.0, 0.0]], ['cheap fare minimum fee', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 340.0, 'new_fare': 310.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 30}, [75.0, 30.0]], ['pct fee exceeds flat', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 1500.0, 'new_fare': 1200.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 200}, [150.0, 300.0]], ['fee larger than residual', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 460.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 48}, [75.0, 40.0]], ['sampled case 1', {'paid': 1227.57, 'new_fare': 1031.14, 'fee': 75.0, 'fee_pct': 20, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 48}, [245.51, 0.0]], ['sampled case 2', {'paid': 762.01, 'new_fare': 1039.32, 'fee': 50.0, 'fee_pct': 15, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 24}, [277.31, 0.0]], ['sampled case 3', {'paid': 1675.54, 'new_fare': 1027.22, 'fee': 50.0, 'fee_pct': 15, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'waiver_h': 24, 'hours_since_ticket': 24}, [0.0, 648.32]]], [['upgrade HIGHER rule', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 900.0, 'new_fare': 1105.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 100}, [295.0, 0.0]], ['downgrade with credit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 450.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 55}, [75.0, 150.0]], ['downgrade forfeit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 425.0, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'hours_since_ticket': 72}, [75.0, 0.0]], ['exactly 24h after ticketing', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 520.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 24}, [20.0, 0.0]], ['cheap fare minimum fee', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 350.0, 'new_fare': 310.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 30}, [75.0, 40.0]], ['pct fee exceeds flat', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 1500.0, 'new_fare': 1200.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 200}, [150.0, 300.0]], ['fee larger than residual', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 460.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 48}, [75.0, 40.0]], ['sampled case 1', {'paid': 938.24, 'new_fare': 955.89, 'fee': 100.0, 'fee_pct': 15, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'waiver_h': 48, 'hours_since_ticket': 57.2}, [117.65, 0.0]], ['sampled case 2', {'paid': 1989.4, 'new_fare': 2128.3, 'fee': 150.0, 'fee_pct': 10, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 12.8}, [138.9, 0.0]], ['sampled case 3', {'paid': 1315.4, 'new_fare': 1527.5, 'fee': 50.0, 'fee_pct': 15, 'fee_rule': 'FLAT', 'residual': 'FORFEIT', 'waiver_h': 48, 'hours_since_ticket': 24}, [212.1, 0.0]]]]
for label, args, expected in fixtures[N-1]:
    check(label, 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
upgrade HIGHER rule	`[276.0, 0.0]`	`[291.0, 0.0]`	Failed
downgrade with credit	`[75.0, 150.0]`	`[75.0, 150.0]`	Passed
downgrade forfeit	`[60.0, 0.0]`	`[75.0, 0.0]`	Failed
exactly 24h after ticketing	`[20.0, 0.0]`	`[20.0, 0.0]`	Passed
cheap fare minimum fee	`[31.0, 0.0]`	`[75.0, 0.0]`	Failed
pct fee exceeds flat	`[75.0, 300.0]`	`[150.0, 300.0]`	Failed
fee larger than residual	`[75.0, 40.0]`	`[75.0, 40.0]`	Passed
sampled case 1	`[50.0, 0.0]`	`[141.78, 0.0]`	Failed
sampled case 2	`[385.89, 0.0]`	`[385.89, 0.0]`	Passed
sampled case 3	`[0.0, 0.0]`	`[0.0, 0.0]`	Passed

SHA-256 / 61a3a7c16362bc05cde07793264087c82c6589ff5765e59b3b2f4b3333d7bd57

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(x):
    paid, new = x['paid'], x['new_fare']
    if x['hours_since_ticket'] <= x['waiver_h']:
        fee = 0.0
    elif x['fee_rule'] == 'FLAT':
        fee = x['fee']
    else:
        fee = x['fee'] + x['fee_pct'] * paid / 100
    collect = max(0.0, new - paid) + fee
    credit = max(0.0, paid - new) if x['residual'] == 'CREDIT' else 0.0
    return [round(collect, 2), round(credit, 2)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['upgrade HIGHER rule', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 900.0, 'new_fare': 1101.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 100}, [291.0, 0.0]], ['downgrade with credit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 450.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 51}, [75.0, 150.0]], ['downgrade forfeit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 421.0, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'hours_since_ticket': 72}, [75.0, 0.0]], ['exactly 24h after ticketing', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 520.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 24}, [20.0, 0.0]], ['cheap fare minimum fee', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 310.0, 'new_fare': 310.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 30}, [75.0, 0.0]], ['pct fee exceeds flat', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 1500.0, 'new_fare': 1200.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 200}, [150.0, 300.0]], ['fee larger than residual', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 460.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 48}, [75.0, 40.0]], ['sampled case 1', {'paid': 945.21, 'new_fare': 746.1, 'fee': 50.0, 'fee_pct': 15, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 397}, [141.78, 0.0]], ['sampled case 2', {'paid': 616.49, 'new_fare': 852.38, 'fee': 150.0, 'fee_pct': 10, 'fee_rule': 'FLAT', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 48}, [385.89, 0.0]], ['sampled case 3', {'paid': 832.44, 'new_fare': 589.1, 'fee': 50.0, 'fee_pct': 15, 'fee_rule': 'FLAT', 'residual': 'FORFEIT', 'waiver_h': 48, 'hours_since_ticket': 24}, [0.0, 0.0]]], [['upgrade HIGHER rule', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 900.0, 'new_fare': 1102.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 100}, [292.0, 0.0]], ['downgrade with credit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 450.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 52}, [75.0, 150.0]], ['downgrade forfeit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 422.0, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'hours_since_ticket': 72}, [75.0, 0.0]], ['exactly 24h after ticketing', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 520.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 24}, [20.0, 0.0]], ['cheap fare minimum fee', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 320.0, 'new_fare': 310.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 30}, [75.0, 10.0]], ['pct fee exceeds flat', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 1500.0, 'new_fare': 1200.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 200}, [150.0, 300.0]], ['fee larger than residual', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 460.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 48}, [75.0, 40.0]], ['sampled case 1', {'paid': 187.06, 'new_fare': 196.65, 'fee': 150.0, 'fee_pct': 15, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 24}, [9.59, 0.0]], ['sampled case 2', {'paid': 1518.15, 'new_fare': 1549.03, 'fee': 150.0, 'fee_pct': 20, 'fee_rule': 'FLAT', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 24}, [30.88, 0.0]], ['sampled case 3', {'paid': 1212.02, 'new_fare': 1432.47, 'fee': 100.0, 'fee_pct': 5, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 48, 'hours_since_ticket': 49}, [320.45, 0.0]]], [['upgrade HIGHER rule', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 900.0, 'new_fare': 1103.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 100}, [293.0, 0.0]], ['downgrade with credit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 450.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 53}, [75.0, 150.0]], ['downgrade forfeit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 423.0, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'hours_since_ticket': 72}, [75.0, 0.0]], ['exactly 24h after ticketing', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 520.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 24}, [20.0, 0.0]], ['cheap fare minimum fee', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 330.0, 'new_fare': 310.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 30}, [75.0, 20.0]], ['pct fee exceeds flat', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 1500.0, 'new_fare': 1200.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 200}, [150.0, 300.0]], ['fee larger than residual', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 460.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 48}, [75.0, 40.0]], ['sampled case 1', {'paid': 1440.92, 'new_fare': 1296.99, 'fee': 75.0, 'fee_pct': 20, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'waiver_h': 48, 'hours_since_ticket': 24}, [0.0, 143.93]], ['sampled case 2', {'paid': 1622.18, 'new_fare': 873.9, 'fee': 150.0, 'fee_pct': 15, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 48}, [243.33, 0.0]], ['sampled case 3', {'paid': 1642.66, 'new_fare': 1568.49, 'fee': 75.0, 'fee_pct': 20, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 48, 'hours_since_ticket': 48}, [0.0, 0.0]]], [['upgrade HIGHER rule', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 900.0, 'new_fare': 1104.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 100}, [294.0, 0.0]], ['downgrade with credit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 450.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 54}, [75.0, 150.0]], ['downgrade forfeit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 424.0, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'hours_since_ticket': 72}, [75.0, 0.0]], ['exactly 24h after ticketing', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 520.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 24}, [20.0, 0.0]], ['cheap fare minimum fee', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 340.0, 'new_fare': 310.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 30}, [75.0, 30.0]], ['pct fee exceeds flat', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 1500.0, 'new_fare': 1200.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 200}, [150.0, 300.0]], ['fee larger than residual', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 460.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 48}, [75.0, 40.0]], ['sampled case 1', {'paid': 1227.57, 'new_fare': 1031.14, 'fee': 75.0, 'fee_pct': 20, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 48}, [245.51, 0.0]], ['sampled case 2', {'paid': 762.01, 'new_fare': 1039.32, 'fee': 50.0, 'fee_pct': 15, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 24}, [277.31, 0.0]], ['sampled case 3', {'paid': 1675.54, 'new_fare': 1027.22, 'fee': 50.0, 'fee_pct': 15, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'waiver_h': 24, 'hours_since_ticket': 24}, [0.0, 648.32]]], [['upgrade HIGHER rule', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 900.0, 'new_fare': 1105.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 100}, [295.0, 0.0]], ['downgrade with credit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 450.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 55}, [75.0, 150.0]], ['downgrade forfeit', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 600.0, 'new_fare': 425.0, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'hours_since_ticket': 72}, [75.0, 0.0]], ['exactly 24h after ticketing', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 520.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 24}, [20.0, 0.0]], ['cheap fare minimum fee', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 350.0, 'new_fare': 310.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 30}, [75.0, 40.0]], ['pct fee exceeds flat', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 1500.0, 'new_fare': 1200.0, 'fee_rule': 'HIGHER', 'residual': 'CREDIT', 'hours_since_ticket': 200}, [150.0, 300.0]], ['fee larger than residual', {'waiver_h': 24, 'fee': 75.0, 'fee_pct': 10, 'paid': 500.0, 'new_fare': 460.0, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'hours_since_ticket': 48}, [75.0, 40.0]], ['sampled case 1', {'paid': 938.24, 'new_fare': 955.89, 'fee': 100.0, 'fee_pct': 15, 'fee_rule': 'FLAT', 'residual': 'CREDIT', 'waiver_h': 48, 'hours_since_ticket': 57.2}, [117.65, 0.0]], ['sampled case 2', {'paid': 1989.4, 'new_fare': 2128.3, 'fee': 150.0, 'fee_pct': 10, 'fee_rule': 'HIGHER', 'residual': 'FORFEIT', 'waiver_h': 24, 'hours_since_ticket': 12.8}, [138.9, 0.0]], ['sampled case 3', {'paid': 1315.4, 'new_fare': 1527.5, 'fee': 50.0, 'fee_pct': 15, 'fee_rule': 'FLAT', 'residual': 'FORFEIT', 'waiver_h': 48, 'hours_since_ticket': 24}, [212.1, 0.0]]]]
for label, args, expected in fixtures[N-1]:
    check(label, 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
upgrade HIGHER rule	`[366.0, 0.0]`	`[291.0, 0.0]`	Failed
downgrade with credit	`[75.0, 150.0]`	`[75.0, 150.0]`	Passed
downgrade forfeit	`[135.0, 0.0]`	`[75.0, 0.0]`	Failed
exactly 24h after ticketing	`[20.0, 0.0]`	`[20.0, 0.0]`	Passed
cheap fare minimum fee	`[106.0, 0.0]`	`[75.0, 0.0]`	Failed
pct fee exceeds flat	`[225.0, 300.0]`	`[150.0, 300.0]`	Failed
fee larger than residual	`[75.0, 40.0]`	`[75.0, 40.0]`	Passed
sampled case 1	`[191.78, 0.0]`	`[141.78, 0.0]`	Failed
sampled case 2	`[385.89, 0.0]`	`[385.89, 0.0]`	Passed
sampled case 3	`[0.0, 0.0]`	`[0.0, 0.0]`	Passed

SHA-256 / ce8a31c28f3b25781952359a0307be7f00cb4828b4926673f1095bbab0e8d03f

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 10 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

Verification & scope

A stipulated toy fare-rule contract with invented constants; it is not an ATPCO or carrier tariff implementation and makes no claim of industry-standard conformance. 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 2026-09-29T14:47:44.136510+00:00.

Case digest / c0d0b39a2821eb1b6d1af8386370c61d97820db437e6a86e5b94efc31596be09