FA-85631 / Ride-hailing fare and surge pricing / Open access

Surge applied to a flat airport fare · case 01

The advertised 45.00 airport flat becomes 90.00 during surge.

Verified by executionVariant 1 · 7 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Flat fares are multiplied by the surge factor.

VERIFIED REPAIR

Never surge flat fares.

Unsuccessful approach: Capping the surge on flat fares still surges them.

Case contract

Zone names are case-insensitive (normalized upper case). A flat fare table keyed "A|B" applies in both directions; a flat fare (0 is a valid promotional flat) is never surged. Otherwise the metered fare is surged (tenths, half up). Airport fees apply separately: the pickup fee of the pickup zone and the dropoff fee of the dropoff zone. Tolls are added last. Return [fare, flat|metered].

Why this case matters

Ride-hailing prices are computed per trip at scale; ordering, unit and boundary slips become systematic over- or under-charging.

1 / The failure

Exit 1

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

N = 1
observations = []
def solve(table, pickup_zone, drop_zone, metered, tolls, surge, airport_fees):
    p, d = pickup_zone.upper(), drop_zone.upper()
    flat = table.get(p + '|' + d, table.get(d + '|' + p))
    if flat is not None:
        fare, kind = (flat * surge * 2 + 10) // 20, 'flat'
    else:
        fare, kind = (metered * surge * 2 + 10) // 20, 'metered'
    fare += airport_fees.get(p, {}).get('pickup', 0) + airport_fees.get(d, {}).get('dropoff', 0)
    return [fare + tolls, kind]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'Dt', 4020, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5250, 'flat']),
  ('partial repair probe: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'UNI', 1583, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4650, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'UNI', 'air', 3817, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4200, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'UNI', 'MID', 1392, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [2688, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'SHUT', 2416, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [0, 'flat']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'UNI', 1886, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5000, 'flat']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'UNI', 'MID', 3959, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [3959, 'metered'])],
 [('regression: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'DT', 2394, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5000, 'flat']),
  ('partial repair probe: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'DT', 1758, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5250, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'Dt', 5666, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5000, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'DT', 4719, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5319, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'UNI', 'Dt', 4427, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4427, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 2639, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5050, 'flat']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'UNI', 1611, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1611, 'metered'])],
 [('regression: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'AIR', 4755, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4800, 'flat']),
  ('partial repair probe: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'Dt', 4524, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5600, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'DT', 1236, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5600, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'air', 2551, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5050, 'flat']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'SHUT', 3196, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [6642, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 2794, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'air', 4676, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5726, 'metered'])],
 [('regression: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'DT', 5371, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5250, 'flat']),
  ('partial repair probe: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'Dt', 3909, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5250, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'AIR', 2322, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4800, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'UNI', 5805, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [8708, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'MID', 3717, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [6176, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'UNI', 'UNI', 4021, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [8042, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'AIR', 1131, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [2247, 'metered'])],
 [('regression: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 2796, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('partial repair probe: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'Dt', 2621, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5000, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'DT', 1792, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5250, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'MID', 2031, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [3647, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'MID', 4946, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [10142, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'air', 3171, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5557, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'AIR', 4585, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5985, 'metered'])]]
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
regression: surge on flat fares	`[7500, 'flat']`	`[5250, 'flat']`	Failed
partial repair probe: surge on flat fares	`[6600, 'flat']`	`[4650, 'flat']`	Failed
second regression	`[8100, 'flat']`	`[4200, 'flat']`	Failed
normal control 1	`[2688, 'metered']`	`[2688, 'metered']`	Passed
normal control 2	`[0, 'flat']`	`[0, 'flat']`	Passed
normal control 3	`[5000, 'flat']`	`[5000, 'flat']`	Passed
normal control 4	`[3959, 'metered']`	`[3959, 'metered']`	Passed

SHA-256 / d8e727f2058a7963edadcbcc9a1fce851852b21d4d878fd667faa1b80d9276e1

2 / The unsuccessful fix

Exit 1

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

N = 1
observations = []
def solve(table, pickup_zone, drop_zone, metered, tolls, surge, airport_fees):
    p, d = pickup_zone.upper(), drop_zone.upper()
    flat = table.get(p + '|' + d, table.get(d + '|' + p))
    if flat is not None:
        fare, kind = (flat * min(surge, 15) * 2 + 10) // 20, 'flat'
    else:
        fare, kind = (metered * surge * 2 + 10) // 20, 'metered'
    fare += airport_fees.get(p, {}).get('pickup', 0) + airport_fees.get(d, {}).get('dropoff', 0)
    return [fare + tolls, kind]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'Dt', 4020, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5250, 'flat']),
  ('partial repair probe: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'UNI', 1583, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4650, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'UNI', 'air', 3817, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4200, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'UNI', 'MID', 1392, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [2688, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'SHUT', 2416, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [0, 'flat']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'UNI', 1886, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5000, 'flat']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'UNI', 'MID', 3959, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [3959, 'metered'])],
 [('regression: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'DT', 2394, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5000, 'flat']),
  ('partial repair probe: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'DT', 1758, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5250, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'Dt', 5666, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5000, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'DT', 4719, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5319, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'UNI', 'Dt', 4427, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4427, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 2639, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5050, 'flat']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'UNI', 1611, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1611, 'metered'])],
 [('regression: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'AIR', 4755, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4800, 'flat']),
  ('partial repair probe: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'Dt', 4524, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5600, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'DT', 1236, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5600, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'air', 2551, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5050, 'flat']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'SHUT', 3196, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [6642, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 2794, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'air', 4676, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5726, 'metered'])],
 [('regression: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'DT', 5371, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5250, 'flat']),
  ('partial repair probe: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'Dt', 3909, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5250, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'AIR', 2322, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4800, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'UNI', 5805, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [8708, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'MID', 3717, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [6176, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'UNI', 'UNI', 4021, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [8042, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'AIR', 1131, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [2247, 'metered'])],
 [('regression: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 2796, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('partial repair probe: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'Dt', 2621, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5000, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'DT', 1792, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5250, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'MID', 2031, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [3647, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'MID', 4946, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [10142, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'air', 3171, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5557, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'AIR', 4585, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5985, 'metered'])]]
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
regression: surge on flat fares	`[7500, 'flat']`	`[5250, 'flat']`	Failed
partial repair probe: surge on flat fares	`[6600, 'flat']`	`[4650, 'flat']`	Failed
second regression	`[6150, 'flat']`	`[4200, 'flat']`	Failed
normal control 1	`[2688, 'metered']`	`[2688, 'metered']`	Passed
normal control 2	`[0, 'flat']`	`[0, 'flat']`	Passed
normal control 3	`[5000, 'flat']`	`[5000, 'flat']`	Passed
normal control 4	`[3959, 'metered']`	`[3959, 'metered']`	Passed

SHA-256 / d0ca5fb97559f28442a3f7a506bddfb3cdd2001dfaa8336d657cd95457b3d463

3 / The verified repair

Exit 0

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

N = 1
observations = []
def solve(table, pickup_zone, drop_zone, metered, tolls, surge, airport_fees):
    p, d = pickup_zone.upper(), drop_zone.upper()
    flat = table.get(p + '|' + d, table.get(d + '|' + p))
    if flat is not None:
        fare, kind = flat, 'flat'
    else:
        fare, kind = (metered * surge * 2 + 10) // 20, 'metered'
    fare += airport_fees.get(p, {}).get('pickup', 0) + airport_fees.get(d, {}).get('dropoff', 0)
    return [fare + tolls, kind]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'Dt', 4020, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5250, 'flat']),
  ('partial repair probe: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'UNI', 1583, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4650, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'UNI', 'air', 3817, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4200, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'UNI', 'MID', 1392, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [2688, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'SHUT', 2416, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [0, 'flat']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'UNI', 1886, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5000, 'flat']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'UNI', 'MID', 3959, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [3959, 'metered'])],
 [('regression: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'DT', 2394, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5000, 'flat']),
  ('partial repair probe: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'DT', 1758, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5250, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'Dt', 5666, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5000, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'DT', 4719, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5319, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'UNI', 'Dt', 4427, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4427, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 2639, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5050, 'flat']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'UNI', 1611, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1611, 'metered'])],
 [('regression: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'AIR', 4755, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4800, 'flat']),
  ('partial repair probe: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'Dt', 4524, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5600, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'DT', 1236, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5600, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'air', 2551, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5050, 'flat']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'SHUT', 3196, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [6642, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 2794, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'air', 4676, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5726, 'metered'])],
 [('regression: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'DT', 5371, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5250, 'flat']),
  ('partial repair probe: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'Dt', 3909, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5250, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'AIR', 2322, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4800, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'UNI', 5805, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [8708, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'MID', 3717, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [6176, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'UNI', 'UNI', 4021, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [8042, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'AIR', 1131, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [2247, 'metered'])],
 [('regression: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 2796, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('partial repair probe: surge on flat fares',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'Dt', 2621, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5000, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'DT', 1792, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5250, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'MID', 2031, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [3647, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'MID', 4946, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [10142, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'air', 3171, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5557, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'AIR', 4585, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5985, 'metered'])]]
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
regression: surge on flat fares	`[5250, 'flat']`	`[5250, 'flat']`	Passed
partial repair probe: surge on flat fares	`[4650, 'flat']`	`[4650, 'flat']`	Passed
second regression	`[4200, 'flat']`	`[4200, 'flat']`	Passed
normal control 1	`[2688, 'metered']`	`[2688, 'metered']`	Passed
normal control 2	`[0, 'flat']`	`[0, 'flat']`	Passed
normal control 3	`[5000, 'flat']`	`[5000, 'flat']`	Passed
normal control 4	`[3959, 'metered']`	`[3959, 'metered']`	Passed

SHA-256 / 9d72f9be9dbd62a72e3b3c68a525393b0cb4cf403a754dd9b5a85f7f994e7531

Verification & scope

A deterministic toy pricing contract stipulated for this example; it does not reproduce the pricing of any real ride-hailing operator or regulator. 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 2026-09-29T14:50:42.224021+00:00.

Case digest / 3f703fb68f00596dcb5a61e6f75580de4c0c66c496a9dcb160239e927402035a