FA-63126 / Insurance premium rating / Open access

Multi-policy discount stacking: Discount groups are added instead of multiplied · case 01

Policies with several discount groups receive too large a discount.

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

ROOT CAUSE

Group factors are combined additively.

VERIFIED REPAIR

Multiply the group factors.

Unsuccessful approach: Keeping only the best group ignores the other groups.

Case contract

Input premium, discounts [[group, code, per mille]], cap per mille, min_premium. A code repeated within a group counts once at its largest value; codes within a group add; groups combine multiplicatively; the total discount 1-product is capped; net = premium*(1-d) rounded half-up, then floored at min_premium.

Why this case matters

Premium rating engines apply ordered tabular rules where one misplaced boundary or step silently misprices policies.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
from fractions import Fraction
N = 1
observations = []
def solve(x):
    groups={}
    for g,code,v in x['discounts']:
        groups.setdefault(g,{})
        groups[g][code]=max(groups[g].get(code,0),v)
    f=Fraction(1)
    for g in sorted(groups):
        f-=Fraction(sum(groups[g].values()),1000)
    d=min(Fraction(x['cap'],1000),1-f)
    net=math.floor(x['premium']*(1-d)+Fraction(1,2))
    return max(net,x['min_premium'])
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['two groups multiply', {'premium': 179834, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 51], ['driver', 'student', 40]], 'cap': 350, 'min_premium': 20000}, 147122], ['duplicate discount code', {'premium': 83536, 'discounts': [['policy', 'home', 100], ['policy', 'home', 80], ['policy', 'life', 30]], 'cap': 350, 'min_premium': 20000}, 72676], ['duplicate code rising value', {'premium': 216432, 'discounts': [['driver', 'safe', 40], ['driver', 'safe', 60], ['vehicle', 'abs', 20]], 'cap': 300, 'min_premium': 20000}, 199377], ['cap binds', {'premium': 295817, 'discounts': [['policy', 'home', 150], ['driver', 'safe', 150], ['vehicle', 'abs', 100], ['vehicle', 'alarm', 50]], 'cap': 250, 'min_premium': 20000}, 221863], ['single group', {'premium': 83079, 'discounts': [['vehicle', 'abs', 45], ['vehicle', 'alarm', 25]], 'cap': 350, 'min_premium': 20000}, 77263], ['minimum premium binds', {'premium': 22100, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 80]], 'cap': 300, 'min_premium': 20000}, 20000], ['capped policy at minimum', {'premium': 28000, 'discounts': [['policy', 'home', 200], ['driver', 'safe', 200]], 'cap': 300, 'min_premium': 20000}, 20000], ['no discounts', {'premium': 114606, 'discounts': [], 'cap': 350, 'min_premium': 20000}, 114606]], [['two groups multiply', {'premium': 259533, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 52], ['driver', 'student', 40]], 'cap': 300, 'min_premium': 20000}, 212090], ['duplicate discount code', {'premium': 222796, 'discounts': [['policy', 'home', 100], ['policy', 'home', 80], ['policy', 'life', 30]], 'cap': 350, 'min_premium': 20000}, 193833], ['duplicate code rising value', {'premium': 264635, 'discounts': [['driver', 'safe', 40], ['driver', 'safe', 60], ['vehicle', 'abs', 20]], 'cap': 300, 'min_premium': 20000}, 243782], ['cap binds', {'premium': 274466, 'discounts': [['policy', 'home', 150], ['driver', 'safe', 150], ['vehicle', 'abs', 100], ['vehicle', 'alarm', 50]], 'cap': 250, 'min_premium': 20000}, 205850], ['single group', {'premium': 122187, 'discounts': [['vehicle', 'abs', 48], ['vehicle', 'alarm', 51]], 'cap': 350, 'min_premium': 20000}, 110090], ['minimum premium binds', {'premium': 22200, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 80]], 'cap': 300, 'min_premium': 20000}, 20000], ['capped policy at minimum', {'premium': 28000, 'discounts': [['policy', 'home', 200], ['driver', 'safe', 200]], 'cap': 300, 'min_premium': 20000}, 20000], ['no discounts', {'premium': 67195, 'discounts': [], 'cap': 300, 'min_premium': 20000}, 67195]], [['two groups multiply', {'premium': 246480, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 53], ['driver', 'student', 40]], 'cap': 300, 'min_premium': 20000}, 201202], ['duplicate discount code', {'premium': 212077, 'discounts': [['policy', 'home', 100], ['policy', 'home', 80], ['policy', 'life', 30]], 'cap': 350, 'min_premium': 20000}, 184507], ['duplicate code rising value', {'premium': 239143, 'discounts': [['driver', 'safe', 40], ['driver', 'safe', 60], ['vehicle', 'abs', 20]], 'cap': 300, 'min_premium': 20000}, 220299], ['cap binds', {'premium': 260788, 'discounts': [['policy', 'home', 150], ['driver', 'safe', 150], ['vehicle', 'abs', 100], ['vehicle', 'alarm', 50]], 'cap': 250, 'min_premium': 20000}, 195591], ['single group', {'premium': 76428, 'discounts': [['vehicle', 'abs', 25], ['vehicle', 'alarm', 25]], 'cap': 350, 'min_premium': 20000}, 72607], ['minimum premium binds', {'premium': 22300, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 80]], 'cap': 350, 'min_premium': 20000}, 20000], ['capped policy at minimum', {'premium': 28000, 'discounts': [['policy', 'home', 200], ['driver', 'safe', 200]], 'cap': 300, 'min_premium': 20000}, 20000], ['no discounts', {'premium': 231596, 'discounts': [], 'cap': 300, 'min_premium': 20000}, 231596]], [['two groups multiply', {'premium': 234855, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 54], ['driver', 'student', 40]], 'cap': 300, 'min_premium': 20000}, 191501], ['duplicate discount code', {'premium': 62000, 'discounts': [['policy', 'home', 100], ['policy', 'home', 80], ['policy', 'life', 30]], 'cap': 300, 'min_premium': 20000}, 53940], ['duplicate code rising value', {'premium': 164924, 'discounts': [['driver', 'safe', 40], ['driver', 'safe', 60], ['vehicle', 'abs', 20]], 'cap': 350, 'min_premium': 20000}, 151928], ['cap binds', {'premium': 160428, 'discounts': [['policy', 'home', 150], ['driver', 'safe', 150], ['vehicle', 'abs', 100], ['vehicle', 'alarm', 50]], 'cap': 250, 'min_premium': 20000}, 120321], ['single group', {'premium': 150010, 'discounts': [['vehicle', 'abs', 53], ['vehicle', 'alarm', 34]], 'cap': 350, 'min_premium': 20000}, 136959], ['minimum premium binds', {'premium': 22400, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 80]], 'cap': 350, 'min_premium': 20000}, 20000], ['capped policy at minimum', {'premium': 28000, 'discounts': [['policy', 'home', 200], ['driver', 'safe', 200]], 'cap': 300, 'min_premium': 20000}, 20000], ['no discounts', {'premium': 64059, 'discounts': [], 'cap': 350, 'min_premium': 20000}, 64059]], [['two groups multiply', {'premium': 70322, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 55], ['driver', 'student', 40]], 'cap': 350, 'min_premium': 20000}, 57277], ['duplicate discount code', {'premium': 120452, 'discounts': [['policy', 'home', 100], ['policy', 'home', 80], ['policy', 'life', 30]], 'cap': 300, 'min_premium': 20000}, 104793], ['duplicate code rising value', {'premium': 89846, 'discounts': [['driver', 'safe', 40], ['driver', 'safe', 60], ['vehicle', 'abs', 20]], 'cap': 350, 'min_premium': 20000}, 82766], ['cap binds', {'premium': 116342, 'discounts': [['policy', 'home', 150], ['driver', 'safe', 150], ['vehicle', 'abs', 100], ['vehicle', 'alarm', 50]], 'cap': 250, 'min_premium': 20000}, 87257], ['single group', {'premium': 214086, 'discounts': [['vehicle', 'abs', 20], ['vehicle', 'alarm', 44]], 'cap': 300, 'min_premium': 20000}, 200384], ['minimum premium binds', {'premium': 22500, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 80]], 'cap': 350, 'min_premium': 20000}, 20000], ['capped policy at minimum', {'premium': 28000, 'discounts': [['policy', 'home', 200], ['driver', 'safe', 200]], 'cap': 300, 'min_premium': 20000}, 20000], ['no discounts', {'premium': 211453, 'discounts': [], 'cap': 300, 'min_premium': 20000}, 211453]]]
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
two groups multiply	`145486`	`147122`	Failed
duplicate discount code	`72676`	`72676`	Passed
duplicate code rising value	`199117`	`199377`	Failed
cap binds	`221863`	`221863`	Passed
single group	`77263`	`77263`	Passed
minimum premium binds	`20000`	`20000`	Passed
capped policy at minimum	`20000`	`20000`	Passed
no discounts	`114606`	`114606`	Passed

SHA-256 / cf59f259dc9117df19e8be7c6ccfb9bb23577ae5769419c25bbf4ea47fb572a8

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
from fractions import Fraction
N = 1
observations = []
def solve(x):
    groups={}
    for g,code,v in x['discounts']:
        groups.setdefault(g,{})
        groups[g][code]=max(groups[g].get(code,0),v)
    f=Fraction(1)
    for g in sorted(groups):
        f=min(f,1-Fraction(sum(groups[g].values()),1000))
    d=min(Fraction(x['cap'],1000),1-f)
    net=math.floor(x['premium']*(1-d)+Fraction(1,2))
    return max(net,x['min_premium'])
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['two groups multiply', {'premium': 179834, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 51], ['driver', 'student', 40]], 'cap': 350, 'min_premium': 20000}, 147122], ['duplicate discount code', {'premium': 83536, 'discounts': [['policy', 'home', 100], ['policy', 'home', 80], ['policy', 'life', 30]], 'cap': 350, 'min_premium': 20000}, 72676], ['duplicate code rising value', {'premium': 216432, 'discounts': [['driver', 'safe', 40], ['driver', 'safe', 60], ['vehicle', 'abs', 20]], 'cap': 300, 'min_premium': 20000}, 199377], ['cap binds', {'premium': 295817, 'discounts': [['policy', 'home', 150], ['driver', 'safe', 150], ['vehicle', 'abs', 100], ['vehicle', 'alarm', 50]], 'cap': 250, 'min_premium': 20000}, 221863], ['single group', {'premium': 83079, 'discounts': [['vehicle', 'abs', 45], ['vehicle', 'alarm', 25]], 'cap': 350, 'min_premium': 20000}, 77263], ['minimum premium binds', {'premium': 22100, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 80]], 'cap': 300, 'min_premium': 20000}, 20000], ['capped policy at minimum', {'premium': 28000, 'discounts': [['policy', 'home', 200], ['driver', 'safe', 200]], 'cap': 300, 'min_premium': 20000}, 20000], ['no discounts', {'premium': 114606, 'discounts': [], 'cap': 350, 'min_premium': 20000}, 114606]], [['two groups multiply', {'premium': 259533, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 52], ['driver', 'student', 40]], 'cap': 300, 'min_premium': 20000}, 212090], ['duplicate discount code', {'premium': 222796, 'discounts': [['policy', 'home', 100], ['policy', 'home', 80], ['policy', 'life', 30]], 'cap': 350, 'min_premium': 20000}, 193833], ['duplicate code rising value', {'premium': 264635, 'discounts': [['driver', 'safe', 40], ['driver', 'safe', 60], ['vehicle', 'abs', 20]], 'cap': 300, 'min_premium': 20000}, 243782], ['cap binds', {'premium': 274466, 'discounts': [['policy', 'home', 150], ['driver', 'safe', 150], ['vehicle', 'abs', 100], ['vehicle', 'alarm', 50]], 'cap': 250, 'min_premium': 20000}, 205850], ['single group', {'premium': 122187, 'discounts': [['vehicle', 'abs', 48], ['vehicle', 'alarm', 51]], 'cap': 350, 'min_premium': 20000}, 110090], ['minimum premium binds', {'premium': 22200, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 80]], 'cap': 300, 'min_premium': 20000}, 20000], ['capped policy at minimum', {'premium': 28000, 'discounts': [['policy', 'home', 200], ['driver', 'safe', 200]], 'cap': 300, 'min_premium': 20000}, 20000], ['no discounts', {'premium': 67195, 'discounts': [], 'cap': 300, 'min_premium': 20000}, 67195]], [['two groups multiply', {'premium': 246480, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 53], ['driver', 'student', 40]], 'cap': 300, 'min_premium': 20000}, 201202], ['duplicate discount code', {'premium': 212077, 'discounts': [['policy', 'home', 100], ['policy', 'home', 80], ['policy', 'life', 30]], 'cap': 350, 'min_premium': 20000}, 184507], ['duplicate code rising value', {'premium': 239143, 'discounts': [['driver', 'safe', 40], ['driver', 'safe', 60], ['vehicle', 'abs', 20]], 'cap': 300, 'min_premium': 20000}, 220299], ['cap binds', {'premium': 260788, 'discounts': [['policy', 'home', 150], ['driver', 'safe', 150], ['vehicle', 'abs', 100], ['vehicle', 'alarm', 50]], 'cap': 250, 'min_premium': 20000}, 195591], ['single group', {'premium': 76428, 'discounts': [['vehicle', 'abs', 25], ['vehicle', 'alarm', 25]], 'cap': 350, 'min_premium': 20000}, 72607], ['minimum premium binds', {'premium': 22300, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 80]], 'cap': 350, 'min_premium': 20000}, 20000], ['capped policy at minimum', {'premium': 28000, 'discounts': [['policy', 'home', 200], ['driver', 'safe', 200]], 'cap': 300, 'min_premium': 20000}, 20000], ['no discounts', {'premium': 231596, 'discounts': [], 'cap': 300, 'min_premium': 20000}, 231596]], [['two groups multiply', {'premium': 234855, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 54], ['driver', 'student', 40]], 'cap': 300, 'min_premium': 20000}, 191501], ['duplicate discount code', {'premium': 62000, 'discounts': [['policy', 'home', 100], ['policy', 'home', 80], ['policy', 'life', 30]], 'cap': 300, 'min_premium': 20000}, 53940], ['duplicate code rising value', {'premium': 164924, 'discounts': [['driver', 'safe', 40], ['driver', 'safe', 60], ['vehicle', 'abs', 20]], 'cap': 350, 'min_premium': 20000}, 151928], ['cap binds', {'premium': 160428, 'discounts': [['policy', 'home', 150], ['driver', 'safe', 150], ['vehicle', 'abs', 100], ['vehicle', 'alarm', 50]], 'cap': 250, 'min_premium': 20000}, 120321], ['single group', {'premium': 150010, 'discounts': [['vehicle', 'abs', 53], ['vehicle', 'alarm', 34]], 'cap': 350, 'min_premium': 20000}, 136959], ['minimum premium binds', {'premium': 22400, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 80]], 'cap': 350, 'min_premium': 20000}, 20000], ['capped policy at minimum', {'premium': 28000, 'discounts': [['policy', 'home', 200], ['driver', 'safe', 200]], 'cap': 300, 'min_premium': 20000}, 20000], ['no discounts', {'premium': 64059, 'discounts': [], 'cap': 350, 'min_premium': 20000}, 64059]], [['two groups multiply', {'premium': 70322, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 55], ['driver', 'student', 40]], 'cap': 350, 'min_premium': 20000}, 57277], ['duplicate discount code', {'premium': 120452, 'discounts': [['policy', 'home', 100], ['policy', 'home', 80], ['policy', 'life', 30]], 'cap': 300, 'min_premium': 20000}, 104793], ['duplicate code rising value', {'premium': 89846, 'discounts': [['driver', 'safe', 40], ['driver', 'safe', 60], ['vehicle', 'abs', 20]], 'cap': 350, 'min_premium': 20000}, 82766], ['cap binds', {'premium': 116342, 'discounts': [['policy', 'home', 150], ['driver', 'safe', 150], ['vehicle', 'abs', 100], ['vehicle', 'alarm', 50]], 'cap': 250, 'min_premium': 20000}, 87257], ['single group', {'premium': 214086, 'discounts': [['vehicle', 'abs', 20], ['vehicle', 'alarm', 44]], 'cap': 300, 'min_premium': 20000}, 200384], ['minimum premium binds', {'premium': 22500, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 80]], 'cap': 350, 'min_premium': 20000}, 20000], ['capped policy at minimum', {'premium': 28000, 'discounts': [['policy', 'home', 200], ['driver', 'safe', 200]], 'cap': 300, 'min_premium': 20000}, 20000], ['no discounts', {'premium': 211453, 'discounts': [], 'cap': 300, 'min_premium': 20000}, 211453]]]
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
two groups multiply	`161851`	`147122`	Failed
duplicate discount code	`72676`	`72676`	Passed
duplicate code rising value	`203446`	`199377`	Failed
cap binds	`251444`	`221863`	Failed
single group	`77263`	`77263`	Passed
minimum premium binds	`20000`	`20000`	Passed
capped policy at minimum	`22400`	`20000`	Failed
no discounts	`114606`	`114606`	Passed

SHA-256 / 076f21078feaf15a5bf66ee205d160b99e63e43ef2cdb553f42ddf9d6dbf655b

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import math
from fractions import Fraction
N = 1
observations = []
def solve(x):
    groups={}
    for g,code,v in x['discounts']:
        groups.setdefault(g,{})
        groups[g][code]=max(groups[g].get(code,0),v)
    f=Fraction(1)
    for g in sorted(groups):
        f*=1-Fraction(sum(groups[g].values()),1000)
    d=min(Fraction(x['cap'],1000),1-f)
    net=math.floor(x['premium']*(1-d)+Fraction(1,2))
    return max(net,x['min_premium'])
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['two groups multiply', {'premium': 179834, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 51], ['driver', 'student', 40]], 'cap': 350, 'min_premium': 20000}, 147122], ['duplicate discount code', {'premium': 83536, 'discounts': [['policy', 'home', 100], ['policy', 'home', 80], ['policy', 'life', 30]], 'cap': 350, 'min_premium': 20000}, 72676], ['duplicate code rising value', {'premium': 216432, 'discounts': [['driver', 'safe', 40], ['driver', 'safe', 60], ['vehicle', 'abs', 20]], 'cap': 300, 'min_premium': 20000}, 199377], ['cap binds', {'premium': 295817, 'discounts': [['policy', 'home', 150], ['driver', 'safe', 150], ['vehicle', 'abs', 100], ['vehicle', 'alarm', 50]], 'cap': 250, 'min_premium': 20000}, 221863], ['single group', {'premium': 83079, 'discounts': [['vehicle', 'abs', 45], ['vehicle', 'alarm', 25]], 'cap': 350, 'min_premium': 20000}, 77263], ['minimum premium binds', {'premium': 22100, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 80]], 'cap': 300, 'min_premium': 20000}, 20000], ['capped policy at minimum', {'premium': 28000, 'discounts': [['policy', 'home', 200], ['driver', 'safe', 200]], 'cap': 300, 'min_premium': 20000}, 20000], ['no discounts', {'premium': 114606, 'discounts': [], 'cap': 350, 'min_premium': 20000}, 114606]], [['two groups multiply', {'premium': 259533, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 52], ['driver', 'student', 40]], 'cap': 300, 'min_premium': 20000}, 212090], ['duplicate discount code', {'premium': 222796, 'discounts': [['policy', 'home', 100], ['policy', 'home', 80], ['policy', 'life', 30]], 'cap': 350, 'min_premium': 20000}, 193833], ['duplicate code rising value', {'premium': 264635, 'discounts': [['driver', 'safe', 40], ['driver', 'safe', 60], ['vehicle', 'abs', 20]], 'cap': 300, 'min_premium': 20000}, 243782], ['cap binds', {'premium': 274466, 'discounts': [['policy', 'home', 150], ['driver', 'safe', 150], ['vehicle', 'abs', 100], ['vehicle', 'alarm', 50]], 'cap': 250, 'min_premium': 20000}, 205850], ['single group', {'premium': 122187, 'discounts': [['vehicle', 'abs', 48], ['vehicle', 'alarm', 51]], 'cap': 350, 'min_premium': 20000}, 110090], ['minimum premium binds', {'premium': 22200, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 80]], 'cap': 300, 'min_premium': 20000}, 20000], ['capped policy at minimum', {'premium': 28000, 'discounts': [['policy', 'home', 200], ['driver', 'safe', 200]], 'cap': 300, 'min_premium': 20000}, 20000], ['no discounts', {'premium': 67195, 'discounts': [], 'cap': 300, 'min_premium': 20000}, 67195]], [['two groups multiply', {'premium': 246480, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 53], ['driver', 'student', 40]], 'cap': 300, 'min_premium': 20000}, 201202], ['duplicate discount code', {'premium': 212077, 'discounts': [['policy', 'home', 100], ['policy', 'home', 80], ['policy', 'life', 30]], 'cap': 350, 'min_premium': 20000}, 184507], ['duplicate code rising value', {'premium': 239143, 'discounts': [['driver', 'safe', 40], ['driver', 'safe', 60], ['vehicle', 'abs', 20]], 'cap': 300, 'min_premium': 20000}, 220299], ['cap binds', {'premium': 260788, 'discounts': [['policy', 'home', 150], ['driver', 'safe', 150], ['vehicle', 'abs', 100], ['vehicle', 'alarm', 50]], 'cap': 250, 'min_premium': 20000}, 195591], ['single group', {'premium': 76428, 'discounts': [['vehicle', 'abs', 25], ['vehicle', 'alarm', 25]], 'cap': 350, 'min_premium': 20000}, 72607], ['minimum premium binds', {'premium': 22300, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 80]], 'cap': 350, 'min_premium': 20000}, 20000], ['capped policy at minimum', {'premium': 28000, 'discounts': [['policy', 'home', 200], ['driver', 'safe', 200]], 'cap': 300, 'min_premium': 20000}, 20000], ['no discounts', {'premium': 231596, 'discounts': [], 'cap': 300, 'min_premium': 20000}, 231596]], [['two groups multiply', {'premium': 234855, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 54], ['driver', 'student', 40]], 'cap': 300, 'min_premium': 20000}, 191501], ['duplicate discount code', {'premium': 62000, 'discounts': [['policy', 'home', 100], ['policy', 'home', 80], ['policy', 'life', 30]], 'cap': 300, 'min_premium': 20000}, 53940], ['duplicate code rising value', {'premium': 164924, 'discounts': [['driver', 'safe', 40], ['driver', 'safe', 60], ['vehicle', 'abs', 20]], 'cap': 350, 'min_premium': 20000}, 151928], ['cap binds', {'premium': 160428, 'discounts': [['policy', 'home', 150], ['driver', 'safe', 150], ['vehicle', 'abs', 100], ['vehicle', 'alarm', 50]], 'cap': 250, 'min_premium': 20000}, 120321], ['single group', {'premium': 150010, 'discounts': [['vehicle', 'abs', 53], ['vehicle', 'alarm', 34]], 'cap': 350, 'min_premium': 20000}, 136959], ['minimum premium binds', {'premium': 22400, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 80]], 'cap': 350, 'min_premium': 20000}, 20000], ['capped policy at minimum', {'premium': 28000, 'discounts': [['policy', 'home', 200], ['driver', 'safe', 200]], 'cap': 300, 'min_premium': 20000}, 20000], ['no discounts', {'premium': 64059, 'discounts': [], 'cap': 350, 'min_premium': 20000}, 64059]], [['two groups multiply', {'premium': 70322, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 55], ['driver', 'student', 40]], 'cap': 350, 'min_premium': 20000}, 57277], ['duplicate discount code', {'premium': 120452, 'discounts': [['policy', 'home', 100], ['policy', 'home', 80], ['policy', 'life', 30]], 'cap': 300, 'min_premium': 20000}, 104793], ['duplicate code rising value', {'premium': 89846, 'discounts': [['driver', 'safe', 40], ['driver', 'safe', 60], ['vehicle', 'abs', 20]], 'cap': 350, 'min_premium': 20000}, 82766], ['cap binds', {'premium': 116342, 'discounts': [['policy', 'home', 150], ['driver', 'safe', 150], ['vehicle', 'abs', 100], ['vehicle', 'alarm', 50]], 'cap': 250, 'min_premium': 20000}, 87257], ['single group', {'premium': 214086, 'discounts': [['vehicle', 'abs', 20], ['vehicle', 'alarm', 44]], 'cap': 300, 'min_premium': 20000}, 200384], ['minimum premium binds', {'premium': 22500, 'discounts': [['policy', 'home', 100], ['driver', 'safe', 80]], 'cap': 350, 'min_premium': 20000}, 20000], ['capped policy at minimum', {'premium': 28000, 'discounts': [['policy', 'home', 200], ['driver', 'safe', 200]], 'cap': 300, 'min_premium': 20000}, 20000], ['no discounts', {'premium': 211453, 'discounts': [], 'cap': 300, 'min_premium': 20000}, 211453]]]
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
two groups multiply	`147122`	`147122`	Passed
duplicate discount code	`72676`	`72676`	Passed
duplicate code rising value	`199377`	`199377`	Passed
cap binds	`221863`	`221863`	Passed
single group	`77263`	`77263`	Passed
minimum premium binds	`20000`	`20000`	Passed
capped policy at minimum	`20000`	`20000`	Passed
no discounts	`114606`	`114606`	Passed

SHA-256 / f98e14812180ea94dbb4d2c9ce412cfab2f5a2868e3a23cf11a4c348598344ed

Verification & scope

A deterministic bounded teaching model of a stipulated toy rating contract. Amounts are integer cents and factors exact rationals; it makes no claim of conformance with any filed rating plan, bureau manual or jurisdiction. 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 2026-09-29T14:47:11.454811+00:00.

Case digest / 87fe2ad2743c83b199efa8dc45d8b1236a443745c5a04ae80c62e6f8c843b2c4