FA-59981 / Inventory cost layering / Open access

Lower of cost and net realizable value: carrying value cap · case 01

Items whose NRV has risen above original cost are written up above cost.

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

ROOT CAUSE

The carrying value is set to NRV without capping at original cost.

VERIFIED REPAIR

Carrying unit = min(original cost, NRV).

Unsuccessful approach: Capping at the prior carrying amount blocks legitimate reversals of earlier write-downs.

Case contract

Input {items:[{sku,qty,cost,price,complete,sell_bp,group}], prior:{sku:carrying unit}}. NRV = price - complete - round-half-up(price*sell_bp/10000), floored at 0. Carrying unit = min(original cost, NRV). Adjustment = qty*(carrying - prior carrying), prior defaulting to original cost (reversals are thereby capped at cost). Group check: write-down per group = max(0, sum qty*cost - sum qty*NRV). Return {items:[[sku,carry,adj]], group_writedown}.

Why this case matters

Inventory valuation and cost-of-goods decisions depend on this rule.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(x):
    res = []
    groups = {}
    for it in x['items']:
        sell = (it['price'] * it['sell_bp'] + 5000) // 10000
        nrv = it['price'] - it['complete'] - sell
        if nrv < 0:
            nrv = 0
        carry = nrv
        prior = x['prior'].get(it['sku'], it['cost'])
        res.append([it['sku'], carry, it['qty'] * (carry - prior)])
        g = groups.setdefault(it['group'], [0, 0])
        g[0] += it['qty'] * it['cost']
        g[1] += it['qty'] * nrv
    gw = {k: max(0, v[0] - v[1]) for k, v in sorted(groups.items())}
    return {'items': res, 'group_writedown': gw}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['write down', {'items': [{'sku': 'A', 'qty': 5, 'cost': 1000, 'price': 1100, 'complete': 100, 'sell_bp': 1001, 'group': 'g1'}], 'prior': {}}, {'items': [['A', 890, -550]], 'group_writedown': {'g1': 550}}], ['no write down', {'items': [{'sku': 'B', 'qty': 2, 'cost': 500, 'price': 900, 'complete': 50, 'sell_bp': 500, 'group': 'g1'}], 'prior': {}}, {'items': [['B', 500, 0]], 'group_writedown': {'g1': 0}}], ['negative nrv', {'items': [{'sku': 'C', 'qty': 3, 'cost': 400, 'price': 300, 'complete': 251, 'sell_bp': 2000, 'group': 'g2'}], 'prior': {}}, {'items': [['C', 0, -1200]], 'group_writedown': {'g2': 1200}}], ['reversal capped', {'items': [{'sku': 'D', 'qty': 4, 'cost': 800, 'price': 1500, 'complete': 0, 'sell_bp': 0, 'group': 'g2'}], 'prior': {'D': 601}}, {'items': [['D', 800, 796]], 'group_writedown': {'g2': 0}}], ['partial reversal', {'items': [{'sku': 'E', 'qty': 1, 'cost': 800, 'price': 850, 'complete': 0, 'sell_bp': 1000, 'group': 'g1'}], 'prior': {'E': 700}}, {'items': [['E', 765, 65]], 'group_writedown': {'g1': 35}}], ['group offset', {'items': [{'sku': 'F', 'qty': 1, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}, {'sku': 'G', 'qty': 1, 'cost': 200, 'price': 601, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}], 'prior': {}}, {'items': [['F', 700, -300], ['G', 200, 0]], 'group_writedown': {'g3': 0}}], ['group loss', {'items': [{'sku': 'H', 'qty': 2, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}, {'sku': 'J', 'qty': 1, 'cost': 200, 'price': 250, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}], 'prior': {'H': 900}}, {'items': [['H', 700, -400], ['J', 200, 0]], 'group_writedown': {'g4': 550}}], ['costly completion', {'items': [{'sku': 'K', 'qty': 1, 'cost': 300, 'price': 1000, 'complete': 900, 'sell_bp': 500, 'group': 'g5'}], 'prior': {}}, {'items': [['K', 50, -250]], 'group_writedown': {'g5': 250}}]], [['write down', {'items': [{'sku': 'A', 'qty': 5, 'cost': 1000, 'price': 1100, 'complete': 100, 'sell_bp': 1002, 'group': 'g1'}], 'prior': {}}, {'items': [['A', 890, -550]], 'group_writedown': {'g1': 550}}], ['no write down', {'items': [{'sku': 'B', 'qty': 2, 'cost': 500, 'price': 900, 'complete': 50, 'sell_bp': 500, 'group': 'g1'}], 'prior': {}}, {'items': [['B', 500, 0]], 'group_writedown': {'g1': 0}}], ['negative nrv', {'items': [{'sku': 'C', 'qty': 3, 'cost': 400, 'price': 300, 'complete': 252, 'sell_bp': 2000, 'group': 'g2'}], 'prior': {}}, {'items': [['C', 0, -1200]], 'group_writedown': {'g2': 1200}}], ['reversal capped', {'items': [{'sku': 'D', 'qty': 4, 'cost': 800, 'price': 1500, 'complete': 0, 'sell_bp': 0, 'group': 'g2'}], 'prior': {'D': 602}}, {'items': [['D', 800, 792]], 'group_writedown': {'g2': 0}}], ['partial reversal', {'items': [{'sku': 'E', 'qty': 1, 'cost': 800, 'price': 850, 'complete': 0, 'sell_bp': 1000, 'group': 'g1'}], 'prior': {'E': 700}}, {'items': [['E', 765, 65]], 'group_writedown': {'g1': 35}}], ['group offset', {'items': [{'sku': 'F', 'qty': 1, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}, {'sku': 'G', 'qty': 1, 'cost': 200, 'price': 602, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}], 'prior': {}}, {'items': [['F', 700, -300], ['G', 200, 0]], 'group_writedown': {'g3': 0}}], ['group loss', {'items': [{'sku': 'H', 'qty': 2, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}, {'sku': 'J', 'qty': 1, 'cost': 200, 'price': 250, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}], 'prior': {'H': 900}}, {'items': [['H', 700, -400], ['J', 200, 0]], 'group_writedown': {'g4': 550}}], ['costly completion', {'items': [{'sku': 'K', 'qty': 1, 'cost': 300, 'price': 1000, 'complete': 900, 'sell_bp': 500, 'group': 'g5'}], 'prior': {}}, {'items': [['K', 50, -250]], 'group_writedown': {'g5': 250}}]], [['write down', {'items': [{'sku': 'A', 'qty': 5, 'cost': 1000, 'price': 1100, 'complete': 100, 'sell_bp': 1003, 'group': 'g1'}], 'prior': {}}, {'items': [['A', 890, -550]], 'group_writedown': {'g1': 550}}], ['no write down', {'items': [{'sku': 'B', 'qty': 2, 'cost': 500, 'price': 900, 'complete': 50, 'sell_bp': 500, 'group': 'g1'}], 'prior': {}}, {'items': [['B', 500, 0]], 'group_writedown': {'g1': 0}}], ['negative nrv', {'items': [{'sku': 'C', 'qty': 3, 'cost': 400, 'price': 300, 'complete': 253, 'sell_bp': 2000, 'group': 'g2'}], 'prior': {}}, {'items': [['C', 0, -1200]], 'group_writedown': {'g2': 1200}}], ['reversal capped', {'items': [{'sku': 'D', 'qty': 4, 'cost': 800, 'price': 1500, 'complete': 0, 'sell_bp': 0, 'group': 'g2'}], 'prior': {'D': 603}}, {'items': [['D', 800, 788]], 'group_writedown': {'g2': 0}}], ['partial reversal', {'items': [{'sku': 'E', 'qty': 1, 'cost': 800, 'price': 850, 'complete': 0, 'sell_bp': 1000, 'group': 'g1'}], 'prior': {'E': 700}}, {'items': [['E', 765, 65]], 'group_writedown': {'g1': 35}}], ['group offset', {'items': [{'sku': 'F', 'qty': 1, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}, {'sku': 'G', 'qty': 1, 'cost': 200, 'price': 603, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}], 'prior': {}}, {'items': [['F', 700, -300], ['G', 200, 0]], 'group_writedown': {'g3': 0}}], ['group loss', {'items': [{'sku': 'H', 'qty': 2, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}, {'sku': 'J', 'qty': 1, 'cost': 200, 'price': 250, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}], 'prior': {'H': 900}}, {'items': [['H', 700, -400], ['J', 200, 0]], 'group_writedown': {'g4': 550}}], ['costly completion', {'items': [{'sku': 'K', 'qty': 1, 'cost': 300, 'price': 1000, 'complete': 900, 'sell_bp': 500, 'group': 'g5'}], 'prior': {}}, {'items': [['K', 50, -250]], 'group_writedown': {'g5': 250}}]], [['write down', {'items': [{'sku': 'A', 'qty': 5, 'cost': 1000, 'price': 1100, 'complete': 100, 'sell_bp': 1004, 'group': 'g1'}], 'prior': {}}, {'items': [['A', 890, -550]], 'group_writedown': {'g1': 550}}], ['no write down', {'items': [{'sku': 'B', 'qty': 2, 'cost': 500, 'price': 900, 'complete': 50, 'sell_bp': 500, 'group': 'g1'}], 'prior': {}}, {'items': [['B', 500, 0]], 'group_writedown': {'g1': 0}}], ['negative nrv', {'items': [{'sku': 'C', 'qty': 3, 'cost': 400, 'price': 300, 'complete': 254, 'sell_bp': 2000, 'group': 'g2'}], 'prior': {}}, {'items': [['C', 0, -1200]], 'group_writedown': {'g2': 1200}}], ['reversal capped', {'items': [{'sku': 'D', 'qty': 4, 'cost': 800, 'price': 1500, 'complete': 0, 'sell_bp': 0, 'group': 'g2'}], 'prior': {'D': 604}}, {'items': [['D', 800, 784]], 'group_writedown': {'g2': 0}}], ['partial reversal', {'items': [{'sku': 'E', 'qty': 1, 'cost': 800, 'price': 850, 'complete': 0, 'sell_bp': 1000, 'group': 'g1'}], 'prior': {'E': 700}}, {'items': [['E', 765, 65]], 'group_writedown': {'g1': 35}}], ['group offset', {'items': [{'sku': 'F', 'qty': 1, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}, {'sku': 'G', 'qty': 1, 'cost': 200, 'price': 604, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}], 'prior': {}}, {'items': [['F', 700, -300], ['G', 200, 0]], 'group_writedown': {'g3': 0}}], ['group loss', {'items': [{'sku': 'H', 'qty': 2, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}, {'sku': 'J', 'qty': 1, 'cost': 200, 'price': 250, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}], 'prior': {'H': 900}}, {'items': [['H', 700, -400], ['J', 200, 0]], 'group_writedown': {'g4': 550}}], ['costly completion', {'items': [{'sku': 'K', 'qty': 1, 'cost': 300, 'price': 1000, 'complete': 900, 'sell_bp': 500, 'group': 'g5'}], 'prior': {}}, {'items': [['K', 50, -250]], 'group_writedown': {'g5': 250}}]], [['write down', {'items': [{'sku': 'A', 'qty': 5, 'cost': 1000, 'price': 1100, 'complete': 100, 'sell_bp': 1005, 'group': 'g1'}], 'prior': {}}, {'items': [['A', 889, -555]], 'group_writedown': {'g1': 555}}], ['no write down', {'items': [{'sku': 'B', 'qty': 2, 'cost': 500, 'price': 900, 'complete': 50, 'sell_bp': 500, 'group': 'g1'}], 'prior': {}}, {'items': [['B', 500, 0]], 'group_writedown': {'g1': 0}}], ['negative nrv', {'items': [{'sku': 'C', 'qty': 3, 'cost': 400, 'price': 300, 'complete': 255, 'sell_bp': 2000, 'group': 'g2'}], 'prior': {}}, {'items': [['C', 0, -1200]], 'group_writedown': {'g2': 1200}}], ['reversal capped', {'items': [{'sku': 'D', 'qty': 4, 'cost': 800, 'price': 1500, 'complete': 0, 'sell_bp': 0, 'group': 'g2'}], 'prior': {'D': 605}}, {'items': [['D', 800, 780]], 'group_writedown': {'g2': 0}}], ['partial reversal', {'items': [{'sku': 'E', 'qty': 1, 'cost': 800, 'price': 850, 'complete': 0, 'sell_bp': 1000, 'group': 'g1'}], 'prior': {'E': 700}}, {'items': [['E', 765, 65]], 'group_writedown': {'g1': 35}}], ['group offset', {'items': [{'sku': 'F', 'qty': 1, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}, {'sku': 'G', 'qty': 1, 'cost': 200, 'price': 605, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}], 'prior': {}}, {'items': [['F', 700, -300], ['G', 200, 0]], 'group_writedown': {'g3': 0}}], ['group loss', {'items': [{'sku': 'H', 'qty': 2, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}, {'sku': 'J', 'qty': 1, 'cost': 200, 'price': 250, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}], 'prior': {'H': 900}}, {'items': [['H', 700, -400], ['J', 200, 0]], 'group_writedown': {'g4': 550}}], ['costly completion', {'items': [{'sku': 'K', 'qty': 1, 'cost': 300, 'price': 1000, 'complete': 900, 'sell_bp': 500, 'group': 'g5'}], 'prior': {}}, {'items': [['K', 50, -250]], 'group_writedown': {'g5': 250}}]]]
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
write down	`{'group_writedown': {'g1': 550}, 'items': [['A', 890, -550]]}`	`{'group_writedown': {'g1': 550}, 'items': [['A', 890, -550]]}`	Passed
no write down	`{'group_writedown': {'g1': 0}, 'items': [['B', 805, 610]]}`	`{'group_writedown': {'g1': 0}, 'items': [['B', 500, 0]]}`	Failed
negative nrv	`{'group_writedown': {'g2': 1200}, 'items': [['C', 0, -1200]]}`	`{'group_writedown': {'g2': 1200}, 'items': [['C', 0, -1200]]}`	Passed
reversal capped	`{'group_writedown': {'g2': 0}, 'items': [['D', 1500, 3596]]}`	`{'group_writedown': {'g2': 0}, 'items': [['D', 800, 796]]}`	Failed
partial reversal	`{'group_writedown': {'g1': 35}, 'items': [['E', 765, 65]]}`	`{'group_writedown': {'g1': 35}, 'items': [['E', 765, 65]]}`	Passed
group offset	`{'group_writedown': {'g3': 0}, 'items': [['F', 700, -300], ['G', 601, 401]]}`	`{'group_writedown': {'g3': 0}, 'items': [['F', 700, -300], ['G', 200, 0]]}`	Failed
group loss	`{'group_writedown': {'g4': 550}, 'items': [['H', 700, -400], ['J', 250, 50]]}`	`{'group_writedown': {'g4': 550}, 'items': [['H', 700, -400], ['J', 200, 0]]}`	Failed
costly completion	`{'group_writedown': {'g5': 250}, 'items': [['K', 50, -250]]}`	`{'group_writedown': {'g5': 250}, 'items': [['K', 50, -250]]}`	Passed

SHA-256 / 8773370a9f91a8a7d364aa69639e7638eb31f00af8ddeafe8e207fe0ef492882

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(x):
    res = []
    groups = {}
    for it in x['items']:
        sell = (it['price'] * it['sell_bp'] + 5000) // 10000
        nrv = it['price'] - it['complete'] - sell
        if nrv < 0:
            nrv = 0
        carry = min(x['prior'].get(it['sku'], it['cost']), nrv)
        prior = x['prior'].get(it['sku'], it['cost'])
        res.append([it['sku'], carry, it['qty'] * (carry - prior)])
        g = groups.setdefault(it['group'], [0, 0])
        g[0] += it['qty'] * it['cost']
        g[1] += it['qty'] * nrv
    gw = {k: max(0, v[0] - v[1]) for k, v in sorted(groups.items())}
    return {'items': res, 'group_writedown': gw}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['write down', {'items': [{'sku': 'A', 'qty': 5, 'cost': 1000, 'price': 1100, 'complete': 100, 'sell_bp': 1001, 'group': 'g1'}], 'prior': {}}, {'items': [['A', 890, -550]], 'group_writedown': {'g1': 550}}], ['no write down', {'items': [{'sku': 'B', 'qty': 2, 'cost': 500, 'price': 900, 'complete': 50, 'sell_bp': 500, 'group': 'g1'}], 'prior': {}}, {'items': [['B', 500, 0]], 'group_writedown': {'g1': 0}}], ['negative nrv', {'items': [{'sku': 'C', 'qty': 3, 'cost': 400, 'price': 300, 'complete': 251, 'sell_bp': 2000, 'group': 'g2'}], 'prior': {}}, {'items': [['C', 0, -1200]], 'group_writedown': {'g2': 1200}}], ['reversal capped', {'items': [{'sku': 'D', 'qty': 4, 'cost': 800, 'price': 1500, 'complete': 0, 'sell_bp': 0, 'group': 'g2'}], 'prior': {'D': 601}}, {'items': [['D', 800, 796]], 'group_writedown': {'g2': 0}}], ['partial reversal', {'items': [{'sku': 'E', 'qty': 1, 'cost': 800, 'price': 850, 'complete': 0, 'sell_bp': 1000, 'group': 'g1'}], 'prior': {'E': 700}}, {'items': [['E', 765, 65]], 'group_writedown': {'g1': 35}}], ['group offset', {'items': [{'sku': 'F', 'qty': 1, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}, {'sku': 'G', 'qty': 1, 'cost': 200, 'price': 601, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}], 'prior': {}}, {'items': [['F', 700, -300], ['G', 200, 0]], 'group_writedown': {'g3': 0}}], ['group loss', {'items': [{'sku': 'H', 'qty': 2, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}, {'sku': 'J', 'qty': 1, 'cost': 200, 'price': 250, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}], 'prior': {'H': 900}}, {'items': [['H', 700, -400], ['J', 200, 0]], 'group_writedown': {'g4': 550}}], ['costly completion', {'items': [{'sku': 'K', 'qty': 1, 'cost': 300, 'price': 1000, 'complete': 900, 'sell_bp': 500, 'group': 'g5'}], 'prior': {}}, {'items': [['K', 50, -250]], 'group_writedown': {'g5': 250}}]], [['write down', {'items': [{'sku': 'A', 'qty': 5, 'cost': 1000, 'price': 1100, 'complete': 100, 'sell_bp': 1002, 'group': 'g1'}], 'prior': {}}, {'items': [['A', 890, -550]], 'group_writedown': {'g1': 550}}], ['no write down', {'items': [{'sku': 'B', 'qty': 2, 'cost': 500, 'price': 900, 'complete': 50, 'sell_bp': 500, 'group': 'g1'}], 'prior': {}}, {'items': [['B', 500, 0]], 'group_writedown': {'g1': 0}}], ['negative nrv', {'items': [{'sku': 'C', 'qty': 3, 'cost': 400, 'price': 300, 'complete': 252, 'sell_bp': 2000, 'group': 'g2'}], 'prior': {}}, {'items': [['C', 0, -1200]], 'group_writedown': {'g2': 1200}}], ['reversal capped', {'items': [{'sku': 'D', 'qty': 4, 'cost': 800, 'price': 1500, 'complete': 0, 'sell_bp': 0, 'group': 'g2'}], 'prior': {'D': 602}}, {'items': [['D', 800, 792]], 'group_writedown': {'g2': 0}}], ['partial reversal', {'items': [{'sku': 'E', 'qty': 1, 'cost': 800, 'price': 850, 'complete': 0, 'sell_bp': 1000, 'group': 'g1'}], 'prior': {'E': 700}}, {'items': [['E', 765, 65]], 'group_writedown': {'g1': 35}}], ['group offset', {'items': [{'sku': 'F', 'qty': 1, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}, {'sku': 'G', 'qty': 1, 'cost': 200, 'price': 602, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}], 'prior': {}}, {'items': [['F', 700, -300], ['G', 200, 0]], 'group_writedown': {'g3': 0}}], ['group loss', {'items': [{'sku': 'H', 'qty': 2, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}, {'sku': 'J', 'qty': 1, 'cost': 200, 'price': 250, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}], 'prior': {'H': 900}}, {'items': [['H', 700, -400], ['J', 200, 0]], 'group_writedown': {'g4': 550}}], ['costly completion', {'items': [{'sku': 'K', 'qty': 1, 'cost': 300, 'price': 1000, 'complete': 900, 'sell_bp': 500, 'group': 'g5'}], 'prior': {}}, {'items': [['K', 50, -250]], 'group_writedown': {'g5': 250}}]], [['write down', {'items': [{'sku': 'A', 'qty': 5, 'cost': 1000, 'price': 1100, 'complete': 100, 'sell_bp': 1003, 'group': 'g1'}], 'prior': {}}, {'items': [['A', 890, -550]], 'group_writedown': {'g1': 550}}], ['no write down', {'items': [{'sku': 'B', 'qty': 2, 'cost': 500, 'price': 900, 'complete': 50, 'sell_bp': 500, 'group': 'g1'}], 'prior': {}}, {'items': [['B', 500, 0]], 'group_writedown': {'g1': 0}}], ['negative nrv', {'items': [{'sku': 'C', 'qty': 3, 'cost': 400, 'price': 300, 'complete': 253, 'sell_bp': 2000, 'group': 'g2'}], 'prior': {}}, {'items': [['C', 0, -1200]], 'group_writedown': {'g2': 1200}}], ['reversal capped', {'items': [{'sku': 'D', 'qty': 4, 'cost': 800, 'price': 1500, 'complete': 0, 'sell_bp': 0, 'group': 'g2'}], 'prior': {'D': 603}}, {'items': [['D', 800, 788]], 'group_writedown': {'g2': 0}}], ['partial reversal', {'items': [{'sku': 'E', 'qty': 1, 'cost': 800, 'price': 850, 'complete': 0, 'sell_bp': 1000, 'group': 'g1'}], 'prior': {'E': 700}}, {'items': [['E', 765, 65]], 'group_writedown': {'g1': 35}}], ['group offset', {'items': [{'sku': 'F', 'qty': 1, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}, {'sku': 'G', 'qty': 1, 'cost': 200, 'price': 603, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}], 'prior': {}}, {'items': [['F', 700, -300], ['G', 200, 0]], 'group_writedown': {'g3': 0}}], ['group loss', {'items': [{'sku': 'H', 'qty': 2, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}, {'sku': 'J', 'qty': 1, 'cost': 200, 'price': 250, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}], 'prior': {'H': 900}}, {'items': [['H', 700, -400], ['J', 200, 0]], 'group_writedown': {'g4': 550}}], ['costly completion', {'items': [{'sku': 'K', 'qty': 1, 'cost': 300, 'price': 1000, 'complete': 900, 'sell_bp': 500, 'group': 'g5'}], 'prior': {}}, {'items': [['K', 50, -250]], 'group_writedown': {'g5': 250}}]], [['write down', {'items': [{'sku': 'A', 'qty': 5, 'cost': 1000, 'price': 1100, 'complete': 100, 'sell_bp': 1004, 'group': 'g1'}], 'prior': {}}, {'items': [['A', 890, -550]], 'group_writedown': {'g1': 550}}], ['no write down', {'items': [{'sku': 'B', 'qty': 2, 'cost': 500, 'price': 900, 'complete': 50, 'sell_bp': 500, 'group': 'g1'}], 'prior': {}}, {'items': [['B', 500, 0]], 'group_writedown': {'g1': 0}}], ['negative nrv', {'items': [{'sku': 'C', 'qty': 3, 'cost': 400, 'price': 300, 'complete': 254, 'sell_bp': 2000, 'group': 'g2'}], 'prior': {}}, {'items': [['C', 0, -1200]], 'group_writedown': {'g2': 1200}}], ['reversal capped', {'items': [{'sku': 'D', 'qty': 4, 'cost': 800, 'price': 1500, 'complete': 0, 'sell_bp': 0, 'group': 'g2'}], 'prior': {'D': 604}}, {'items': [['D', 800, 784]], 'group_writedown': {'g2': 0}}], ['partial reversal', {'items': [{'sku': 'E', 'qty': 1, 'cost': 800, 'price': 850, 'complete': 0, 'sell_bp': 1000, 'group': 'g1'}], 'prior': {'E': 700}}, {'items': [['E', 765, 65]], 'group_writedown': {'g1': 35}}], ['group offset', {'items': [{'sku': 'F', 'qty': 1, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}, {'sku': 'G', 'qty': 1, 'cost': 200, 'price': 604, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}], 'prior': {}}, {'items': [['F', 700, -300], ['G', 200, 0]], 'group_writedown': {'g3': 0}}], ['group loss', {'items': [{'sku': 'H', 'qty': 2, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}, {'sku': 'J', 'qty': 1, 'cost': 200, 'price': 250, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}], 'prior': {'H': 900}}, {'items': [['H', 700, -400], ['J', 200, 0]], 'group_writedown': {'g4': 550}}], ['costly completion', {'items': [{'sku': 'K', 'qty': 1, 'cost': 300, 'price': 1000, 'complete': 900, 'sell_bp': 500, 'group': 'g5'}], 'prior': {}}, {'items': [['K', 50, -250]], 'group_writedown': {'g5': 250}}]], [['write down', {'items': [{'sku': 'A', 'qty': 5, 'cost': 1000, 'price': 1100, 'complete': 100, 'sell_bp': 1005, 'group': 'g1'}], 'prior': {}}, {'items': [['A', 889, -555]], 'group_writedown': {'g1': 555}}], ['no write down', {'items': [{'sku': 'B', 'qty': 2, 'cost': 500, 'price': 900, 'complete': 50, 'sell_bp': 500, 'group': 'g1'}], 'prior': {}}, {'items': [['B', 500, 0]], 'group_writedown': {'g1': 0}}], ['negative nrv', {'items': [{'sku': 'C', 'qty': 3, 'cost': 400, 'price': 300, 'complete': 255, 'sell_bp': 2000, 'group': 'g2'}], 'prior': {}}, {'items': [['C', 0, -1200]], 'group_writedown': {'g2': 1200}}], ['reversal capped', {'items': [{'sku': 'D', 'qty': 4, 'cost': 800, 'price': 1500, 'complete': 0, 'sell_bp': 0, 'group': 'g2'}], 'prior': {'D': 605}}, {'items': [['D', 800, 780]], 'group_writedown': {'g2': 0}}], ['partial reversal', {'items': [{'sku': 'E', 'qty': 1, 'cost': 800, 'price': 850, 'complete': 0, 'sell_bp': 1000, 'group': 'g1'}], 'prior': {'E': 700}}, {'items': [['E', 765, 65]], 'group_writedown': {'g1': 35}}], ['group offset', {'items': [{'sku': 'F', 'qty': 1, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}, {'sku': 'G', 'qty': 1, 'cost': 200, 'price': 605, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}], 'prior': {}}, {'items': [['F', 700, -300], ['G', 200, 0]], 'group_writedown': {'g3': 0}}], ['group loss', {'items': [{'sku': 'H', 'qty': 2, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}, {'sku': 'J', 'qty': 1, 'cost': 200, 'price': 250, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}], 'prior': {'H': 900}}, {'items': [['H', 700, -400], ['J', 200, 0]], 'group_writedown': {'g4': 550}}], ['costly completion', {'items': [{'sku': 'K', 'qty': 1, 'cost': 300, 'price': 1000, 'complete': 900, 'sell_bp': 500, 'group': 'g5'}], 'prior': {}}, {'items': [['K', 50, -250]], 'group_writedown': {'g5': 250}}]]]
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
write down	`{'group_writedown': {'g1': 550}, 'items': [['A', 890, -550]]}`	`{'group_writedown': {'g1': 550}, 'items': [['A', 890, -550]]}`	Passed
no write down	`{'group_writedown': {'g1': 0}, 'items': [['B', 500, 0]]}`	`{'group_writedown': {'g1': 0}, 'items': [['B', 500, 0]]}`	Passed
negative nrv	`{'group_writedown': {'g2': 1200}, 'items': [['C', 0, -1200]]}`	`{'group_writedown': {'g2': 1200}, 'items': [['C', 0, -1200]]}`	Passed
reversal capped	`{'group_writedown': {'g2': 0}, 'items': [['D', 601, 0]]}`	`{'group_writedown': {'g2': 0}, 'items': [['D', 800, 796]]}`	Failed
partial reversal	`{'group_writedown': {'g1': 35}, 'items': [['E', 700, 0]]}`	`{'group_writedown': {'g1': 35}, 'items': [['E', 765, 65]]}`	Failed
group offset	`{'group_writedown': {'g3': 0}, 'items': [['F', 700, -300], ['G', 200, 0]]}`	`{'group_writedown': {'g3': 0}, 'items': [['F', 700, -300], ['G', 200, 0]]}`	Passed
group loss	`{'group_writedown': {'g4': 550}, 'items': [['H', 700, -400], ['J', 200, 0]]}`	`{'group_writedown': {'g4': 550}, 'items': [['H', 700, -400], ['J', 200, 0]]}`	Passed
costly completion	`{'group_writedown': {'g5': 250}, 'items': [['K', 50, -250]]}`	`{'group_writedown': {'g5': 250}, 'items': [['K', 50, -250]]}`	Passed

SHA-256 / af6dced3db9f281d69d3ff329b6082b3310966c4609cfbee3bd6d49bed12fc13

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(x):
    res = []
    groups = {}
    for it in x['items']:
        sell = (it['price'] * it['sell_bp'] + 5000) // 10000
        nrv = it['price'] - it['complete'] - sell
        if nrv < 0:
            nrv = 0
        carry = min(it['cost'], nrv)
        prior = x['prior'].get(it['sku'], it['cost'])
        res.append([it['sku'], carry, it['qty'] * (carry - prior)])
        g = groups.setdefault(it['group'], [0, 0])
        g[0] += it['qty'] * it['cost']
        g[1] += it['qty'] * nrv
    gw = {k: max(0, v[0] - v[1]) for k, v in sorted(groups.items())}
    return {'items': res, 'group_writedown': gw}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['write down', {'items': [{'sku': 'A', 'qty': 5, 'cost': 1000, 'price': 1100, 'complete': 100, 'sell_bp': 1001, 'group': 'g1'}], 'prior': {}}, {'items': [['A', 890, -550]], 'group_writedown': {'g1': 550}}], ['no write down', {'items': [{'sku': 'B', 'qty': 2, 'cost': 500, 'price': 900, 'complete': 50, 'sell_bp': 500, 'group': 'g1'}], 'prior': {}}, {'items': [['B', 500, 0]], 'group_writedown': {'g1': 0}}], ['negative nrv', {'items': [{'sku': 'C', 'qty': 3, 'cost': 400, 'price': 300, 'complete': 251, 'sell_bp': 2000, 'group': 'g2'}], 'prior': {}}, {'items': [['C', 0, -1200]], 'group_writedown': {'g2': 1200}}], ['reversal capped', {'items': [{'sku': 'D', 'qty': 4, 'cost': 800, 'price': 1500, 'complete': 0, 'sell_bp': 0, 'group': 'g2'}], 'prior': {'D': 601}}, {'items': [['D', 800, 796]], 'group_writedown': {'g2': 0}}], ['partial reversal', {'items': [{'sku': 'E', 'qty': 1, 'cost': 800, 'price': 850, 'complete': 0, 'sell_bp': 1000, 'group': 'g1'}], 'prior': {'E': 700}}, {'items': [['E', 765, 65]], 'group_writedown': {'g1': 35}}], ['group offset', {'items': [{'sku': 'F', 'qty': 1, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}, {'sku': 'G', 'qty': 1, 'cost': 200, 'price': 601, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}], 'prior': {}}, {'items': [['F', 700, -300], ['G', 200, 0]], 'group_writedown': {'g3': 0}}], ['group loss', {'items': [{'sku': 'H', 'qty': 2, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}, {'sku': 'J', 'qty': 1, 'cost': 200, 'price': 250, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}], 'prior': {'H': 900}}, {'items': [['H', 700, -400], ['J', 200, 0]], 'group_writedown': {'g4': 550}}], ['costly completion', {'items': [{'sku': 'K', 'qty': 1, 'cost': 300, 'price': 1000, 'complete': 900, 'sell_bp': 500, 'group': 'g5'}], 'prior': {}}, {'items': [['K', 50, -250]], 'group_writedown': {'g5': 250}}]], [['write down', {'items': [{'sku': 'A', 'qty': 5, 'cost': 1000, 'price': 1100, 'complete': 100, 'sell_bp': 1002, 'group': 'g1'}], 'prior': {}}, {'items': [['A', 890, -550]], 'group_writedown': {'g1': 550}}], ['no write down', {'items': [{'sku': 'B', 'qty': 2, 'cost': 500, 'price': 900, 'complete': 50, 'sell_bp': 500, 'group': 'g1'}], 'prior': {}}, {'items': [['B', 500, 0]], 'group_writedown': {'g1': 0}}], ['negative nrv', {'items': [{'sku': 'C', 'qty': 3, 'cost': 400, 'price': 300, 'complete': 252, 'sell_bp': 2000, 'group': 'g2'}], 'prior': {}}, {'items': [['C', 0, -1200]], 'group_writedown': {'g2': 1200}}], ['reversal capped', {'items': [{'sku': 'D', 'qty': 4, 'cost': 800, 'price': 1500, 'complete': 0, 'sell_bp': 0, 'group': 'g2'}], 'prior': {'D': 602}}, {'items': [['D', 800, 792]], 'group_writedown': {'g2': 0}}], ['partial reversal', {'items': [{'sku': 'E', 'qty': 1, 'cost': 800, 'price': 850, 'complete': 0, 'sell_bp': 1000, 'group': 'g1'}], 'prior': {'E': 700}}, {'items': [['E', 765, 65]], 'group_writedown': {'g1': 35}}], ['group offset', {'items': [{'sku': 'F', 'qty': 1, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}, {'sku': 'G', 'qty': 1, 'cost': 200, 'price': 602, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}], 'prior': {}}, {'items': [['F', 700, -300], ['G', 200, 0]], 'group_writedown': {'g3': 0}}], ['group loss', {'items': [{'sku': 'H', 'qty': 2, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}, {'sku': 'J', 'qty': 1, 'cost': 200, 'price': 250, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}], 'prior': {'H': 900}}, {'items': [['H', 700, -400], ['J', 200, 0]], 'group_writedown': {'g4': 550}}], ['costly completion', {'items': [{'sku': 'K', 'qty': 1, 'cost': 300, 'price': 1000, 'complete': 900, 'sell_bp': 500, 'group': 'g5'}], 'prior': {}}, {'items': [['K', 50, -250]], 'group_writedown': {'g5': 250}}]], [['write down', {'items': [{'sku': 'A', 'qty': 5, 'cost': 1000, 'price': 1100, 'complete': 100, 'sell_bp': 1003, 'group': 'g1'}], 'prior': {}}, {'items': [['A', 890, -550]], 'group_writedown': {'g1': 550}}], ['no write down', {'items': [{'sku': 'B', 'qty': 2, 'cost': 500, 'price': 900, 'complete': 50, 'sell_bp': 500, 'group': 'g1'}], 'prior': {}}, {'items': [['B', 500, 0]], 'group_writedown': {'g1': 0}}], ['negative nrv', {'items': [{'sku': 'C', 'qty': 3, 'cost': 400, 'price': 300, 'complete': 253, 'sell_bp': 2000, 'group': 'g2'}], 'prior': {}}, {'items': [['C', 0, -1200]], 'group_writedown': {'g2': 1200}}], ['reversal capped', {'items': [{'sku': 'D', 'qty': 4, 'cost': 800, 'price': 1500, 'complete': 0, 'sell_bp': 0, 'group': 'g2'}], 'prior': {'D': 603}}, {'items': [['D', 800, 788]], 'group_writedown': {'g2': 0}}], ['partial reversal', {'items': [{'sku': 'E', 'qty': 1, 'cost': 800, 'price': 850, 'complete': 0, 'sell_bp': 1000, 'group': 'g1'}], 'prior': {'E': 700}}, {'items': [['E', 765, 65]], 'group_writedown': {'g1': 35}}], ['group offset', {'items': [{'sku': 'F', 'qty': 1, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}, {'sku': 'G', 'qty': 1, 'cost': 200, 'price': 603, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}], 'prior': {}}, {'items': [['F', 700, -300], ['G', 200, 0]], 'group_writedown': {'g3': 0}}], ['group loss', {'items': [{'sku': 'H', 'qty': 2, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}, {'sku': 'J', 'qty': 1, 'cost': 200, 'price': 250, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}], 'prior': {'H': 900}}, {'items': [['H', 700, -400], ['J', 200, 0]], 'group_writedown': {'g4': 550}}], ['costly completion', {'items': [{'sku': 'K', 'qty': 1, 'cost': 300, 'price': 1000, 'complete': 900, 'sell_bp': 500, 'group': 'g5'}], 'prior': {}}, {'items': [['K', 50, -250]], 'group_writedown': {'g5': 250}}]], [['write down', {'items': [{'sku': 'A', 'qty': 5, 'cost': 1000, 'price': 1100, 'complete': 100, 'sell_bp': 1004, 'group': 'g1'}], 'prior': {}}, {'items': [['A', 890, -550]], 'group_writedown': {'g1': 550}}], ['no write down', {'items': [{'sku': 'B', 'qty': 2, 'cost': 500, 'price': 900, 'complete': 50, 'sell_bp': 500, 'group': 'g1'}], 'prior': {}}, {'items': [['B', 500, 0]], 'group_writedown': {'g1': 0}}], ['negative nrv', {'items': [{'sku': 'C', 'qty': 3, 'cost': 400, 'price': 300, 'complete': 254, 'sell_bp': 2000, 'group': 'g2'}], 'prior': {}}, {'items': [['C', 0, -1200]], 'group_writedown': {'g2': 1200}}], ['reversal capped', {'items': [{'sku': 'D', 'qty': 4, 'cost': 800, 'price': 1500, 'complete': 0, 'sell_bp': 0, 'group': 'g2'}], 'prior': {'D': 604}}, {'items': [['D', 800, 784]], 'group_writedown': {'g2': 0}}], ['partial reversal', {'items': [{'sku': 'E', 'qty': 1, 'cost': 800, 'price': 850, 'complete': 0, 'sell_bp': 1000, 'group': 'g1'}], 'prior': {'E': 700}}, {'items': [['E', 765, 65]], 'group_writedown': {'g1': 35}}], ['group offset', {'items': [{'sku': 'F', 'qty': 1, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}, {'sku': 'G', 'qty': 1, 'cost': 200, 'price': 604, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}], 'prior': {}}, {'items': [['F', 700, -300], ['G', 200, 0]], 'group_writedown': {'g3': 0}}], ['group loss', {'items': [{'sku': 'H', 'qty': 2, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}, {'sku': 'J', 'qty': 1, 'cost': 200, 'price': 250, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}], 'prior': {'H': 900}}, {'items': [['H', 700, -400], ['J', 200, 0]], 'group_writedown': {'g4': 550}}], ['costly completion', {'items': [{'sku': 'K', 'qty': 1, 'cost': 300, 'price': 1000, 'complete': 900, 'sell_bp': 500, 'group': 'g5'}], 'prior': {}}, {'items': [['K', 50, -250]], 'group_writedown': {'g5': 250}}]], [['write down', {'items': [{'sku': 'A', 'qty': 5, 'cost': 1000, 'price': 1100, 'complete': 100, 'sell_bp': 1005, 'group': 'g1'}], 'prior': {}}, {'items': [['A', 889, -555]], 'group_writedown': {'g1': 555}}], ['no write down', {'items': [{'sku': 'B', 'qty': 2, 'cost': 500, 'price': 900, 'complete': 50, 'sell_bp': 500, 'group': 'g1'}], 'prior': {}}, {'items': [['B', 500, 0]], 'group_writedown': {'g1': 0}}], ['negative nrv', {'items': [{'sku': 'C', 'qty': 3, 'cost': 400, 'price': 300, 'complete': 255, 'sell_bp': 2000, 'group': 'g2'}], 'prior': {}}, {'items': [['C', 0, -1200]], 'group_writedown': {'g2': 1200}}], ['reversal capped', {'items': [{'sku': 'D', 'qty': 4, 'cost': 800, 'price': 1500, 'complete': 0, 'sell_bp': 0, 'group': 'g2'}], 'prior': {'D': 605}}, {'items': [['D', 800, 780]], 'group_writedown': {'g2': 0}}], ['partial reversal', {'items': [{'sku': 'E', 'qty': 1, 'cost': 800, 'price': 850, 'complete': 0, 'sell_bp': 1000, 'group': 'g1'}], 'prior': {'E': 700}}, {'items': [['E', 765, 65]], 'group_writedown': {'g1': 35}}], ['group offset', {'items': [{'sku': 'F', 'qty': 1, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}, {'sku': 'G', 'qty': 1, 'cost': 200, 'price': 605, 'complete': 0, 'sell_bp': 0, 'group': 'g3'}], 'prior': {}}, {'items': [['F', 700, -300], ['G', 200, 0]], 'group_writedown': {'g3': 0}}], ['group loss', {'items': [{'sku': 'H', 'qty': 2, 'cost': 1000, 'price': 700, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}, {'sku': 'J', 'qty': 1, 'cost': 200, 'price': 250, 'complete': 0, 'sell_bp': 0, 'group': 'g4'}], 'prior': {'H': 900}}, {'items': [['H', 700, -400], ['J', 200, 0]], 'group_writedown': {'g4': 550}}], ['costly completion', {'items': [{'sku': 'K', 'qty': 1, 'cost': 300, 'price': 1000, 'complete': 900, 'sell_bp': 500, 'group': 'g5'}], 'prior': {}}, {'items': [['K', 50, -250]], 'group_writedown': {'g5': 250}}]]]
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
write down	`{'group_writedown': {'g1': 550}, 'items': [['A', 890, -550]]}`	`{'group_writedown': {'g1': 550}, 'items': [['A', 890, -550]]}`	Passed
no write down	`{'group_writedown': {'g1': 0}, 'items': [['B', 500, 0]]}`	`{'group_writedown': {'g1': 0}, 'items': [['B', 500, 0]]}`	Passed
negative nrv	`{'group_writedown': {'g2': 1200}, 'items': [['C', 0, -1200]]}`	`{'group_writedown': {'g2': 1200}, 'items': [['C', 0, -1200]]}`	Passed
reversal capped	`{'group_writedown': {'g2': 0}, 'items': [['D', 800, 796]]}`	`{'group_writedown': {'g2': 0}, 'items': [['D', 800, 796]]}`	Passed
partial reversal	`{'group_writedown': {'g1': 35}, 'items': [['E', 765, 65]]}`	`{'group_writedown': {'g1': 35}, 'items': [['E', 765, 65]]}`	Passed
group offset	`{'group_writedown': {'g3': 0}, 'items': [['F', 700, -300], ['G', 200, 0]]}`	`{'group_writedown': {'g3': 0}, 'items': [['F', 700, -300], ['G', 200, 0]]}`	Passed
group loss	`{'group_writedown': {'g4': 550}, 'items': [['H', 700, -400], ['J', 200, 0]]}`	`{'group_writedown': {'g4': 550}, 'items': [['H', 700, -400], ['J', 200, 0]]}`	Passed
costly completion	`{'group_writedown': {'g5': 250}, 'items': [['K', 50, -250]]}`	`{'group_writedown': {'g5': 250}, 'items': [['K', 50, -250]]}`	Passed

SHA-256 / cab7615eb088898bedc5511cbbba4cef678413df4b02fa2c7e837fdbbd4b6245

Verification & scope

Stipulated bounded teaching model with explicit toy rules; not an accounting-standard implementation. 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 2026-09-29T14:46:41.451996+00:00.

Case digest / dd0aab7a0a46cdad4b60a5c6cb7b138f3772f8684789a7a5bbecbeed48b28b8c