FA-85626 / Ride-hailing fare and surge pricing / Open access

Flat fare only applies in the stored direction · case 01

Downtown-to-airport trips are metered while airport-to-downtown is flat.

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

ROOT CAUSE

The flat table is looked up in one direction only.

VERIFIED REPAIR

Try both key orders, keeping falsy values such as 0.

Unsuccessful approach: Chaining with or discards a stored flat of 0 and falls back to the meter.

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)
    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: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 3608, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4800, 'flat']),
  ('partial repair probe: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'SHUT', 4805, 600, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [600, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'SHUT', 5208, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [250, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'Dt', 1699, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [3398, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'SHUT', 3856, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [7712, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'DT', 1127, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [2254, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'UNI', 2552, 600, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5704, 'metered'])],
 [('regression: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'Dt', 1073, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [0, 'flat']),
  ('partial repair probe: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'SHUT', 931, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [600, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'AIR', 3359, 600, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'AIR', 2443, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [3343, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'UNI', 923, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1846, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'Dt', 3022, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [3272, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'UNI', 805, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1208, 'metered'])],
 [('regression: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'air', 3515, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('partial repair probe: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'SHUT', 2597, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [250, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'DT', 4747, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [0, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'air', 2328, 600, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5556, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'MID', 5158, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5158, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'AIR', 1806, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4109, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'MID', 1753, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1753, 'metered'])],
 [('regression: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'Dt', 1321, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [250, 'flat']),
  ('partial repair probe: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'SHUT', 5412, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [250, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 880, 600, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'MID', 3538, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [7326, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'MID', 3425, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [6850, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'SHUT', 4765, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [7748, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'MID', 1553, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [2830, 'metered'])],
 [('regression: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'AIR', 3392, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4800, 'flat']),
  ('partial repair probe: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'SHUT', 2417, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [250, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 3231, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'Dt', 1302, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1902, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'DT', 5689, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [11378, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'SHUT', 4147, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4897, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'SHUT', 1371, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1971, '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: reverse direction lookup	`[5712, 'metered']`	`[4800, 'flat']`	Failed
partial repair probe: reverse direction lookup	`[600, 'flat']`	`[600, 'flat']`	Passed
second regression	`[250, 'flat']`	`[250, 'flat']`	Passed
normal control 1	`[3398, 'metered']`	`[3398, 'metered']`	Passed
normal control 2	`[7712, 'metered']`	`[7712, 'metered']`	Passed
normal control 3	`[2254, 'metered']`	`[2254, 'metered']`	Passed
normal control 4	`[5704, 'metered']`	`[5704, 'metered']`	Passed

SHA-256 / 90df3f5ff91f0718f2c3a6fd755425237a1083f3f63293f609c1cb5e3d0f24a4

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) or 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: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 3608, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4800, 'flat']),
  ('partial repair probe: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'SHUT', 4805, 600, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [600, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'SHUT', 5208, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [250, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'Dt', 1699, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [3398, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'SHUT', 3856, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [7712, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'DT', 1127, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [2254, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'UNI', 2552, 600, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5704, 'metered'])],
 [('regression: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'Dt', 1073, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [0, 'flat']),
  ('partial repair probe: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'SHUT', 931, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [600, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'AIR', 3359, 600, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'AIR', 2443, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [3343, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'UNI', 923, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1846, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'Dt', 3022, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [3272, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'UNI', 805, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1208, 'metered'])],
 [('regression: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'air', 3515, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('partial repair probe: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'SHUT', 2597, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [250, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'DT', 4747, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [0, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'air', 2328, 600, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5556, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'MID', 5158, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5158, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'AIR', 1806, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4109, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'MID', 1753, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1753, 'metered'])],
 [('regression: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'Dt', 1321, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [250, 'flat']),
  ('partial repair probe: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'SHUT', 5412, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [250, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 880, 600, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'MID', 3538, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [7326, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'MID', 3425, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [6850, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'SHUT', 4765, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [7748, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'MID', 1553, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [2830, 'metered'])],
 [('regression: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'AIR', 3392, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4800, 'flat']),
  ('partial repair probe: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'SHUT', 2417, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [250, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 3231, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'Dt', 1302, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1902, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'DT', 5689, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [11378, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'SHUT', 4147, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4897, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'SHUT', 1371, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1971, '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: reverse direction lookup	`[4800, 'flat']`	`[4800, 'flat']`	Passed
partial repair probe: reverse direction lookup	`[10210, 'metered']`	`[600, 'flat']`	Failed
second regression	`[8062, 'metered']`	`[250, 'flat']`	Failed
normal control 1	`[3398, 'metered']`	`[3398, 'metered']`	Passed
normal control 2	`[7712, 'metered']`	`[7712, 'metered']`	Passed
normal control 3	`[2254, 'metered']`	`[2254, 'metered']`	Passed
normal control 4	`[5704, 'metered']`	`[5704, 'metered']`	Passed

SHA-256 / 062b4127acbd97a175a3324c4e56e35100abc683931fe784ea6e9828815162d3

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: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 3608, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4800, 'flat']),
  ('partial repair probe: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'SHUT', 4805, 600, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [600, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'SHUT', 5208, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [250, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'Dt', 1699, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [3398, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'SHUT', 3856, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [7712, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'DT', 1127, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [2254, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'UNI', 2552, 600, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5704, 'metered'])],
 [('regression: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'Dt', 1073, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [0, 'flat']),
  ('partial repair probe: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'SHUT', 931, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [600, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'AIR', 3359, 600, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'AIR', 2443, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [3343, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'UNI', 923, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1846, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'Dt', 3022, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [3272, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'UNI', 805, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1208, 'metered'])],
 [('regression: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'air', 3515, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('partial repair probe: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'SHUT', 2597, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [250, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'DT', 4747, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [0, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'air', 2328, 600, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5556, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'MID', 5158, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5158, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'AIR', 1806, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4109, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'MID', 1753, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1753, 'metered'])],
 [('regression: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'Dt', 1321, 250, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [250, 'flat']),
  ('partial repair probe: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'SHUT', 5412, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [250, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 880, 600, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'MID', 3538, 250, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [7326, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'MID', 3425, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [6850, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'SHUT', 'SHUT', 4765, 600, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [7748, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'AIR', 'MID', 1553, 0, 15,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [2830, 'metered'])],
 [('regression: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'AIR', 3392, 0, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4800, 'flat']),
  ('partial repair probe: reverse direction lookup',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'SHUT', 2417, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [250, 'flat']),
  ('second regression',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'DT', 'air', 3231, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [5400, 'flat']),
  ('normal control 1',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'Dt', 1302, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1902, 'metered']),
  ('normal control 2',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'Dt', 'DT', 5689, 0, 20,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [11378, 'metered']),
  ('normal control 3',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'air', 'SHUT', 4147, 250, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [4897, 'metered']),
  ('normal control 4',
   [{'AIR|DT': 4500, 'AIR|UNI': 3900, 'DT|SHUT': 0}, 'MID', 'SHUT', 1371, 600, 10,
    {'AIR': {'dropoff': 300, 'pickup': 500}}],
   [1971, '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: reverse direction lookup	`[4800, 'flat']`	`[4800, 'flat']`	Passed
partial repair probe: reverse direction lookup	`[600, 'flat']`	`[600, 'flat']`	Passed
second regression	`[250, 'flat']`	`[250, 'flat']`	Passed
normal control 1	`[3398, 'metered']`	`[3398, 'metered']`	Passed
normal control 2	`[7712, 'metered']`	`[7712, 'metered']`	Passed
normal control 3	`[2254, 'metered']`	`[2254, 'metered']`	Passed
normal control 4	`[5704, 'metered']`	`[5704, 'metered']`	Passed

SHA-256 / f342e12ad7af8bb75e20dbad632859c4aea59e79651759ccdb61e160a85d30c0

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 2026-09-29T14:50:42.189799+00:00.

Case digest / 0a38f0d8cfa4ef38dcc7df7474154308028caad207e5094994c292a9fb510eb5