FA-95496 / Shipping rate zone lookup / Open access

Rate card: new card ignored on its first day · case 01

Shipments on the effective date of a new card are rated with the previous card.

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

ROOT CAUSE

The effective-from comparison excludes the effective date.

VERIFIED REPAIR

A card applies from its effective date inclusive.

Unsuccessful approach: Comparing only year and month starts cards on the first of their month.

Case contract

cards [[card_id, effective_from, expires or None, version]] with dates "Y-M-D" that may lack zero padding. A card applies when effective_from <= ship date < expires. Choose the latest effective_from, then highest version, then smallest card_id. None -> "NO_CARD".

Why this case matters

Carriers publish dated rate cards; each shipment must use the card in force on its ship date.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(cards, ship_date):
    def d(s):
        return tuple(int(x) for x in s.split('-'))
    ship = d(ship_date)
    best = None
    for cid, frm, exp, ver in cards:
        if d(frm) >= ship:
            continue
        if exp is not None and ship >= d(exp):
            continue
        key = (d(frm), ver)
        if best is None or key > best[0] or (key == best[0] and cid < best[1]):
            best = (key, cid)
    return best[1] if best else 'NO_CARD'
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['effective same day', [[['A', '2026-3-1', None, 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'A'], ['generated mix 21', [[['R0', '2026-2-1', '2026-10-1', 1], ['R1', '2026-10-1', '2026-10-1', 2], ['R2', '2026-2-1', '2026-11-1', 1], ['R3', '2026-01-15', '2026-10-1', 2], ['R4', '2026-1-5', '2026-2-1', 1]], '2026-1-5'], 'R4'], ['unpadded month', [[['A', '2026-2-1', None, 1], ['B', '2026-10-1', None, 1]], '2026-10-15'], 'B'], ['version tie', [[['A', '2026-1-1', None, 1], ['B', '2026-1-1', None, 2]], '2026-5-1'], 'B'], ['future only', [[['A', '2027-1-1', None, 1]], '2026-5-1'], 'NO_CARD'], ['expiry exclusive', [[['A', '2026-1-1', '2026-3-1', 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'B'], ['id tie', [[['Z', '2026-1-1', None, 2], ['M', '2026-1-1', None, 2]], '2026-5-1'], 'M'], ['generated mix 8', [[['R0', '2026-10-1', '2026-10-1', 1], ['R1', '2026-1-5', None, 3], ['R2', '2026-10-1', '2026-11-1', 3], ['R3', '2026-2-1', None, 3], ['R4', '2026-10-1', None, 3]], '2025-12-31'], 'NO_CARD']], [['generated mix 28', [[['R0', '2026-2-1', '2026-10-1', 1]], '2026-2-1'], 'R0'], ['generated mix 12', [[['R0', '2026-01-15', '2026-2-1', 3], ['R1', '2026-11-1', '2026-11-1', 1]], '2026-1-5'], 'NO_CARD'], ['version tie', [[['A', '2026-1-1', None, 1], ['B', '2026-1-1', None, 2]], '2026-5-1'], 'B'], ['future only', [[['A', '2027-1-1', None, 1]], '2026-5-1'], 'NO_CARD'], ['expiry exclusive', [[['A', '2026-1-1', '2026-3-1', 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'B'], ['generated mix 9', [[['R0', '2026-01-15', '2026-2-1', 1], ['R1', '2025-12-31', '2026-2-1', 3], ['R2', '2026-9-30', '2026-10-1', 3], ['R3', '2026-10-1', '2026-2-1', 1]], '2025-12-31'], 'R1'], ['generated mix 18', [[['R0', '2026-10-1', None, 3], ['R1', '2026-10-1', None, 2], ['R2', '2026-10-1', '2026-2-1', 1], ['R3', '2026-01-15', '2026-2-1', 2], ['R4', '2025-12-31', '2026-11-1', 3]], '2026-10-15'], 'R0'], ['generated mix 26', [[['R0', '2026-2-1', None, 2], ['R1', '2025-12-31', '2026-11-1', 3], ['R2', '2025-12-31', None, 2], ['R3', '2026-9-30', None, 2]], '2026-3-15'], 'R0']], [['generated mix 9', [[['R0', '2026-01-15', '2026-2-1', 1], ['R1', '2025-12-31', '2026-2-1', 3], ['R2', '2026-9-30', '2026-10-1', 3], ['R3', '2026-10-1', '2026-2-1', 1]], '2025-12-31'], 'R1'], ['generated mix 21', [[['R0', '2026-2-1', '2026-10-1', 1], ['R1', '2026-10-1', '2026-10-1', 2], ['R2', '2026-2-1', '2026-11-1', 1], ['R3', '2026-01-15', '2026-10-1', 2], ['R4', '2026-1-5', '2026-2-1', 1]], '2026-1-5'], 'R4'], ['unpadded month', [[['A', '2026-2-1', None, 1], ['B', '2026-10-1', None, 1]], '2026-10-15'], 'B'], ['effective same day', [[['A', '2026-3-1', None, 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'A'], ['id tie', [[['Z', '2026-1-1', None, 2], ['M', '2026-1-1', None, 2]], '2026-5-1'], 'M'], ['generated mix 22', [[['R0', '2026-2-1', '2026-2-1', 2], ['R1', '2026-9-30', '2026-2-1', 1], ['R2', '2026-9-30', '2026-11-1', 2], ['R3', '2026-2-1', '2026-2-1', 1], ['R4', '2026-2-1', '2026-10-1', 3]], '2026-3-15'], 'R4'], ['generated mix 30', [[['R0', '2026-1-5', '2026-2-1', 1], ['R1', '2026-11-1', '2026-2-1', 1], ['R2', '2025-12-31', '2026-2-1', 2], ['R3', '2026-10-1', '2026-11-1', 3]], '2026-01-15'], 'R0'], ['generated mix 38', [[['R0', '2026-10-1', '2026-2-1', 2], ['R1', '2026-01-15', '2026-10-1', 1], ['R2', '2026-1-5', None, 1], ['R3', '2026-1-5', '2026-11-1', 3]], '2026-10-15'], 'R3']], [['generated mix 47', [[['R0', '2026-2-1', '2026-11-1', 3], ['R1', '2025-12-31', '2026-10-1', 1], ['R2', '2026-10-1', '2026-11-1', 1], ['R3', '2026-10-1', '2026-10-1', 2]], '2026-2-1'], 'R0'], ['generated mix 12', [[['R0', '2026-01-15', '2026-2-1', 3], ['R1', '2026-11-1', '2026-11-1', 1]], '2026-1-5'], 'NO_CARD'], ['version tie', [[['A', '2026-1-1', None, 1], ['B', '2026-1-1', None, 2]], '2026-5-1'], 'B'], ['future only', [[['A', '2027-1-1', None, 1]], '2026-5-1'], 'NO_CARD'], ['expiry exclusive', [[['A', '2026-1-1', '2026-3-1', 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'B'], ['generated mix 32', [[['R0', '2026-2-1', None, 1]], '2026-10-1'], 'R0'], ['generated mix 40', [[['R0', '2026-10-1', '2026-2-1', 1], ['R1', '2026-11-1', '2026-2-1', 2], ['R2', '2026-9-30', None, 2], ['R3', '2026-1-5', '2026-2-1', 1]], '2025-12-31'], 'NO_CARD'], ['generated mix 49', [[['R0', '2026-10-1', '2026-10-1', 1], ['R1', '2026-1-5', '2026-2-1', 3], ['R2', '2026-2-1', None, 2], ['R3', '2026-9-30', None, 1], ['R4', '2026-11-1', '2026-11-1', 3]], '2026-10-1'], 'R3']], [['generated mix 21', [[['R0', '2026-2-1', '2026-10-1', 1], ['R1', '2026-10-1', '2026-10-1', 2], ['R2', '2026-2-1', '2026-11-1', 1], ['R3', '2026-01-15', '2026-10-1', 2], ['R4', '2026-1-5', '2026-2-1', 1]], '2026-1-5'], 'R4'], ['unpadded month', [[['A', '2026-2-1', None, 1], ['B', '2026-10-1', None, 1]], '2026-10-15'], 'B'], ['effective same day', [[['A', '2026-3-1', None, 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'A'], ['id tie', [[['Z', '2026-1-1', None, 2], ['M', '2026-1-1', None, 2]], '2026-5-1'], 'M'], ['generated mix 43', [[['R0', '2026-11-1', '2026-10-1', 2], ['R1', '2026-9-30', None, 3], ['R2', '2026-2-1', '2026-11-1', 3], ['R3', '2025-12-31', '2026-2-1', 2], ['R4', '2026-1-5', '2026-2-1', 1]], '2026-3-15'], 'R2'], ['generated mix 51', [[['R0', '2026-9-30', '2026-10-1', 2], ['R1', '2026-1-5', None, 3], ['R2', '2026-01-15', None, 2], ['R3', '2026-2-1', '2026-11-1', 2]], '2026-10-1'], 'R3'], ['generated mix 59', [[['R0', '2025-12-31', None, 2]], '2026-11-1'], 'R0'], ['generated mix 67', [[['R0', '2026-11-1', None, 3], ['R1', '2026-1-5', '2026-2-1', 2]], '2026-2-1'], 'NO_CARD']]]
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
effective same day	`B`	`A`	Failed
generated mix 21	`NO_CARD`	`R4`	Failed
unpadded month	`B`	`B`	Passed
version tie	`B`	`B`	Passed
future only	`NO_CARD`	`NO_CARD`	Passed
expiry exclusive	`B`	`B`	Passed
id tie	`M`	`M`	Passed
generated mix 8	`NO_CARD`	`NO_CARD`	Passed

SHA-256 / ffac30b2854fbfe71128b7ec9c4a48507421dcb989d7c3121a397bfd5748d9c4

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(cards, ship_date):
    def d(s):
        return tuple(int(x) for x in s.split('-'))
    ship = d(ship_date)
    best = None
    for cid, frm, exp, ver in cards:
        if d(frm)[:2] > ship[:2]:
            continue
        if exp is not None and ship >= d(exp):
            continue
        key = (d(frm), ver)
        if best is None or key > best[0] or (key == best[0] and cid < best[1]):
            best = (key, cid)
    return best[1] if best else 'NO_CARD'
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['effective same day', [[['A', '2026-3-1', None, 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'A'], ['generated mix 21', [[['R0', '2026-2-1', '2026-10-1', 1], ['R1', '2026-10-1', '2026-10-1', 2], ['R2', '2026-2-1', '2026-11-1', 1], ['R3', '2026-01-15', '2026-10-1', 2], ['R4', '2026-1-5', '2026-2-1', 1]], '2026-1-5'], 'R4'], ['unpadded month', [[['A', '2026-2-1', None, 1], ['B', '2026-10-1', None, 1]], '2026-10-15'], 'B'], ['version tie', [[['A', '2026-1-1', None, 1], ['B', '2026-1-1', None, 2]], '2026-5-1'], 'B'], ['future only', [[['A', '2027-1-1', None, 1]], '2026-5-1'], 'NO_CARD'], ['expiry exclusive', [[['A', '2026-1-1', '2026-3-1', 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'B'], ['id tie', [[['Z', '2026-1-1', None, 2], ['M', '2026-1-1', None, 2]], '2026-5-1'], 'M'], ['generated mix 8', [[['R0', '2026-10-1', '2026-10-1', 1], ['R1', '2026-1-5', None, 3], ['R2', '2026-10-1', '2026-11-1', 3], ['R3', '2026-2-1', None, 3], ['R4', '2026-10-1', None, 3]], '2025-12-31'], 'NO_CARD']], [['generated mix 28', [[['R0', '2026-2-1', '2026-10-1', 1]], '2026-2-1'], 'R0'], ['generated mix 12', [[['R0', '2026-01-15', '2026-2-1', 3], ['R1', '2026-11-1', '2026-11-1', 1]], '2026-1-5'], 'NO_CARD'], ['version tie', [[['A', '2026-1-1', None, 1], ['B', '2026-1-1', None, 2]], '2026-5-1'], 'B'], ['future only', [[['A', '2027-1-1', None, 1]], '2026-5-1'], 'NO_CARD'], ['expiry exclusive', [[['A', '2026-1-1', '2026-3-1', 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'B'], ['generated mix 9', [[['R0', '2026-01-15', '2026-2-1', 1], ['R1', '2025-12-31', '2026-2-1', 3], ['R2', '2026-9-30', '2026-10-1', 3], ['R3', '2026-10-1', '2026-2-1', 1]], '2025-12-31'], 'R1'], ['generated mix 18', [[['R0', '2026-10-1', None, 3], ['R1', '2026-10-1', None, 2], ['R2', '2026-10-1', '2026-2-1', 1], ['R3', '2026-01-15', '2026-2-1', 2], ['R4', '2025-12-31', '2026-11-1', 3]], '2026-10-15'], 'R0'], ['generated mix 26', [[['R0', '2026-2-1', None, 2], ['R1', '2025-12-31', '2026-11-1', 3], ['R2', '2025-12-31', None, 2], ['R3', '2026-9-30', None, 2]], '2026-3-15'], 'R0']], [['generated mix 9', [[['R0', '2026-01-15', '2026-2-1', 1], ['R1', '2025-12-31', '2026-2-1', 3], ['R2', '2026-9-30', '2026-10-1', 3], ['R3', '2026-10-1', '2026-2-1', 1]], '2025-12-31'], 'R1'], ['generated mix 21', [[['R0', '2026-2-1', '2026-10-1', 1], ['R1', '2026-10-1', '2026-10-1', 2], ['R2', '2026-2-1', '2026-11-1', 1], ['R3', '2026-01-15', '2026-10-1', 2], ['R4', '2026-1-5', '2026-2-1', 1]], '2026-1-5'], 'R4'], ['unpadded month', [[['A', '2026-2-1', None, 1], ['B', '2026-10-1', None, 1]], '2026-10-15'], 'B'], ['effective same day', [[['A', '2026-3-1', None, 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'A'], ['id tie', [[['Z', '2026-1-1', None, 2], ['M', '2026-1-1', None, 2]], '2026-5-1'], 'M'], ['generated mix 22', [[['R0', '2026-2-1', '2026-2-1', 2], ['R1', '2026-9-30', '2026-2-1', 1], ['R2', '2026-9-30', '2026-11-1', 2], ['R3', '2026-2-1', '2026-2-1', 1], ['R4', '2026-2-1', '2026-10-1', 3]], '2026-3-15'], 'R4'], ['generated mix 30', [[['R0', '2026-1-5', '2026-2-1', 1], ['R1', '2026-11-1', '2026-2-1', 1], ['R2', '2025-12-31', '2026-2-1', 2], ['R3', '2026-10-1', '2026-11-1', 3]], '2026-01-15'], 'R0'], ['generated mix 38', [[['R0', '2026-10-1', '2026-2-1', 2], ['R1', '2026-01-15', '2026-10-1', 1], ['R2', '2026-1-5', None, 1], ['R3', '2026-1-5', '2026-11-1', 3]], '2026-10-15'], 'R3']], [['generated mix 47', [[['R0', '2026-2-1', '2026-11-1', 3], ['R1', '2025-12-31', '2026-10-1', 1], ['R2', '2026-10-1', '2026-11-1', 1], ['R3', '2026-10-1', '2026-10-1', 2]], '2026-2-1'], 'R0'], ['generated mix 12', [[['R0', '2026-01-15', '2026-2-1', 3], ['R1', '2026-11-1', '2026-11-1', 1]], '2026-1-5'], 'NO_CARD'], ['version tie', [[['A', '2026-1-1', None, 1], ['B', '2026-1-1', None, 2]], '2026-5-1'], 'B'], ['future only', [[['A', '2027-1-1', None, 1]], '2026-5-1'], 'NO_CARD'], ['expiry exclusive', [[['A', '2026-1-1', '2026-3-1', 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'B'], ['generated mix 32', [[['R0', '2026-2-1', None, 1]], '2026-10-1'], 'R0'], ['generated mix 40', [[['R0', '2026-10-1', '2026-2-1', 1], ['R1', '2026-11-1', '2026-2-1', 2], ['R2', '2026-9-30', None, 2], ['R3', '2026-1-5', '2026-2-1', 1]], '2025-12-31'], 'NO_CARD'], ['generated mix 49', [[['R0', '2026-10-1', '2026-10-1', 1], ['R1', '2026-1-5', '2026-2-1', 3], ['R2', '2026-2-1', None, 2], ['R3', '2026-9-30', None, 1], ['R4', '2026-11-1', '2026-11-1', 3]], '2026-10-1'], 'R3']], [['generated mix 21', [[['R0', '2026-2-1', '2026-10-1', 1], ['R1', '2026-10-1', '2026-10-1', 2], ['R2', '2026-2-1', '2026-11-1', 1], ['R3', '2026-01-15', '2026-10-1', 2], ['R4', '2026-1-5', '2026-2-1', 1]], '2026-1-5'], 'R4'], ['unpadded month', [[['A', '2026-2-1', None, 1], ['B', '2026-10-1', None, 1]], '2026-10-15'], 'B'], ['effective same day', [[['A', '2026-3-1', None, 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'A'], ['id tie', [[['Z', '2026-1-1', None, 2], ['M', '2026-1-1', None, 2]], '2026-5-1'], 'M'], ['generated mix 43', [[['R0', '2026-11-1', '2026-10-1', 2], ['R1', '2026-9-30', None, 3], ['R2', '2026-2-1', '2026-11-1', 3], ['R3', '2025-12-31', '2026-2-1', 2], ['R4', '2026-1-5', '2026-2-1', 1]], '2026-3-15'], 'R2'], ['generated mix 51', [[['R0', '2026-9-30', '2026-10-1', 2], ['R1', '2026-1-5', None, 3], ['R2', '2026-01-15', None, 2], ['R3', '2026-2-1', '2026-11-1', 2]], '2026-10-1'], 'R3'], ['generated mix 59', [[['R0', '2025-12-31', None, 2]], '2026-11-1'], 'R0'], ['generated mix 67', [[['R0', '2026-11-1', None, 3], ['R1', '2026-1-5', '2026-2-1', 2]], '2026-2-1'], 'NO_CARD']]]
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
effective same day	`A`	`A`	Passed
generated mix 21	`R3`	`R4`	Failed
unpadded month	`B`	`B`	Passed
version tie	`B`	`B`	Passed
future only	`NO_CARD`	`NO_CARD`	Passed
expiry exclusive	`B`	`B`	Passed
id tie	`M`	`M`	Passed
generated mix 8	`NO_CARD`	`NO_CARD`	Passed

SHA-256 / 4f8f0952db45c81d64aed11f3ffd5ebc5265330da66ac29aef90a396e0b2bcc7

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(cards, ship_date):
    def d(s):
        return tuple(int(x) for x in s.split('-'))
    ship = d(ship_date)
    best = None
    for cid, frm, exp, ver in cards:
        if d(frm) > ship:
            continue
        if exp is not None and ship >= d(exp):
            continue
        key = (d(frm), ver)
        if best is None or key > best[0] or (key == best[0] and cid < best[1]):
            best = (key, cid)
    return best[1] if best else 'NO_CARD'
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['effective same day', [[['A', '2026-3-1', None, 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'A'], ['generated mix 21', [[['R0', '2026-2-1', '2026-10-1', 1], ['R1', '2026-10-1', '2026-10-1', 2], ['R2', '2026-2-1', '2026-11-1', 1], ['R3', '2026-01-15', '2026-10-1', 2], ['R4', '2026-1-5', '2026-2-1', 1]], '2026-1-5'], 'R4'], ['unpadded month', [[['A', '2026-2-1', None, 1], ['B', '2026-10-1', None, 1]], '2026-10-15'], 'B'], ['version tie', [[['A', '2026-1-1', None, 1], ['B', '2026-1-1', None, 2]], '2026-5-1'], 'B'], ['future only', [[['A', '2027-1-1', None, 1]], '2026-5-1'], 'NO_CARD'], ['expiry exclusive', [[['A', '2026-1-1', '2026-3-1', 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'B'], ['id tie', [[['Z', '2026-1-1', None, 2], ['M', '2026-1-1', None, 2]], '2026-5-1'], 'M'], ['generated mix 8', [[['R0', '2026-10-1', '2026-10-1', 1], ['R1', '2026-1-5', None, 3], ['R2', '2026-10-1', '2026-11-1', 3], ['R3', '2026-2-1', None, 3], ['R4', '2026-10-1', None, 3]], '2025-12-31'], 'NO_CARD']], [['generated mix 28', [[['R0', '2026-2-1', '2026-10-1', 1]], '2026-2-1'], 'R0'], ['generated mix 12', [[['R0', '2026-01-15', '2026-2-1', 3], ['R1', '2026-11-1', '2026-11-1', 1]], '2026-1-5'], 'NO_CARD'], ['version tie', [[['A', '2026-1-1', None, 1], ['B', '2026-1-1', None, 2]], '2026-5-1'], 'B'], ['future only', [[['A', '2027-1-1', None, 1]], '2026-5-1'], 'NO_CARD'], ['expiry exclusive', [[['A', '2026-1-1', '2026-3-1', 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'B'], ['generated mix 9', [[['R0', '2026-01-15', '2026-2-1', 1], ['R1', '2025-12-31', '2026-2-1', 3], ['R2', '2026-9-30', '2026-10-1', 3], ['R3', '2026-10-1', '2026-2-1', 1]], '2025-12-31'], 'R1'], ['generated mix 18', [[['R0', '2026-10-1', None, 3], ['R1', '2026-10-1', None, 2], ['R2', '2026-10-1', '2026-2-1', 1], ['R3', '2026-01-15', '2026-2-1', 2], ['R4', '2025-12-31', '2026-11-1', 3]], '2026-10-15'], 'R0'], ['generated mix 26', [[['R0', '2026-2-1', None, 2], ['R1', '2025-12-31', '2026-11-1', 3], ['R2', '2025-12-31', None, 2], ['R3', '2026-9-30', None, 2]], '2026-3-15'], 'R0']], [['generated mix 9', [[['R0', '2026-01-15', '2026-2-1', 1], ['R1', '2025-12-31', '2026-2-1', 3], ['R2', '2026-9-30', '2026-10-1', 3], ['R3', '2026-10-1', '2026-2-1', 1]], '2025-12-31'], 'R1'], ['generated mix 21', [[['R0', '2026-2-1', '2026-10-1', 1], ['R1', '2026-10-1', '2026-10-1', 2], ['R2', '2026-2-1', '2026-11-1', 1], ['R3', '2026-01-15', '2026-10-1', 2], ['R4', '2026-1-5', '2026-2-1', 1]], '2026-1-5'], 'R4'], ['unpadded month', [[['A', '2026-2-1', None, 1], ['B', '2026-10-1', None, 1]], '2026-10-15'], 'B'], ['effective same day', [[['A', '2026-3-1', None, 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'A'], ['id tie', [[['Z', '2026-1-1', None, 2], ['M', '2026-1-1', None, 2]], '2026-5-1'], 'M'], ['generated mix 22', [[['R0', '2026-2-1', '2026-2-1', 2], ['R1', '2026-9-30', '2026-2-1', 1], ['R2', '2026-9-30', '2026-11-1', 2], ['R3', '2026-2-1', '2026-2-1', 1], ['R4', '2026-2-1', '2026-10-1', 3]], '2026-3-15'], 'R4'], ['generated mix 30', [[['R0', '2026-1-5', '2026-2-1', 1], ['R1', '2026-11-1', '2026-2-1', 1], ['R2', '2025-12-31', '2026-2-1', 2], ['R3', '2026-10-1', '2026-11-1', 3]], '2026-01-15'], 'R0'], ['generated mix 38', [[['R0', '2026-10-1', '2026-2-1', 2], ['R1', '2026-01-15', '2026-10-1', 1], ['R2', '2026-1-5', None, 1], ['R3', '2026-1-5', '2026-11-1', 3]], '2026-10-15'], 'R3']], [['generated mix 47', [[['R0', '2026-2-1', '2026-11-1', 3], ['R1', '2025-12-31', '2026-10-1', 1], ['R2', '2026-10-1', '2026-11-1', 1], ['R3', '2026-10-1', '2026-10-1', 2]], '2026-2-1'], 'R0'], ['generated mix 12', [[['R0', '2026-01-15', '2026-2-1', 3], ['R1', '2026-11-1', '2026-11-1', 1]], '2026-1-5'], 'NO_CARD'], ['version tie', [[['A', '2026-1-1', None, 1], ['B', '2026-1-1', None, 2]], '2026-5-1'], 'B'], ['future only', [[['A', '2027-1-1', None, 1]], '2026-5-1'], 'NO_CARD'], ['expiry exclusive', [[['A', '2026-1-1', '2026-3-1', 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'B'], ['generated mix 32', [[['R0', '2026-2-1', None, 1]], '2026-10-1'], 'R0'], ['generated mix 40', [[['R0', '2026-10-1', '2026-2-1', 1], ['R1', '2026-11-1', '2026-2-1', 2], ['R2', '2026-9-30', None, 2], ['R3', '2026-1-5', '2026-2-1', 1]], '2025-12-31'], 'NO_CARD'], ['generated mix 49', [[['R0', '2026-10-1', '2026-10-1', 1], ['R1', '2026-1-5', '2026-2-1', 3], ['R2', '2026-2-1', None, 2], ['R3', '2026-9-30', None, 1], ['R4', '2026-11-1', '2026-11-1', 3]], '2026-10-1'], 'R3']], [['generated mix 21', [[['R0', '2026-2-1', '2026-10-1', 1], ['R1', '2026-10-1', '2026-10-1', 2], ['R2', '2026-2-1', '2026-11-1', 1], ['R3', '2026-01-15', '2026-10-1', 2], ['R4', '2026-1-5', '2026-2-1', 1]], '2026-1-5'], 'R4'], ['unpadded month', [[['A', '2026-2-1', None, 1], ['B', '2026-10-1', None, 1]], '2026-10-15'], 'B'], ['effective same day', [[['A', '2026-3-1', None, 1], ['B', '2025-1-1', None, 1]], '2026-3-1'], 'A'], ['id tie', [[['Z', '2026-1-1', None, 2], ['M', '2026-1-1', None, 2]], '2026-5-1'], 'M'], ['generated mix 43', [[['R0', '2026-11-1', '2026-10-1', 2], ['R1', '2026-9-30', None, 3], ['R2', '2026-2-1', '2026-11-1', 3], ['R3', '2025-12-31', '2026-2-1', 2], ['R4', '2026-1-5', '2026-2-1', 1]], '2026-3-15'], 'R2'], ['generated mix 51', [[['R0', '2026-9-30', '2026-10-1', 2], ['R1', '2026-1-5', None, 3], ['R2', '2026-01-15', None, 2], ['R3', '2026-2-1', '2026-11-1', 2]], '2026-10-1'], 'R3'], ['generated mix 59', [[['R0', '2025-12-31', None, 2]], '2026-11-1'], 'R0'], ['generated mix 67', [[['R0', '2026-11-1', None, 3], ['R1', '2026-1-5', '2026-2-1', 2]], '2026-2-1'], 'NO_CARD']]]
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
effective same day	`A`	`A`	Passed
generated mix 21	`R4`	`R4`	Passed
unpadded month	`B`	`B`	Passed
version tie	`B`	`B`	Passed
future only	`NO_CARD`	`NO_CARD`	Passed
expiry exclusive	`B`	`B`	Passed
id tie	`M`	`M`	Passed
generated mix 8	`NO_CARD`	`NO_CARD`	Passed

SHA-256 / 088c139229bb1415dfc8ee4f38bd92df7567aa73b7c02bd0540b5fd8e46cceb9

Verification & scope

Stipulated date format and selection policy. 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 2026-09-29T14:52:14.266556+00:00.

Case digest / 9a3dad6d902b625f82bcbad57ee7f147682ab167e0856bbe24bb4698b5570289