FAILURE MAP
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FA-93061 / EV charging session scheduling / Open access

Ready-by departure latest start: zero request handling · case 01

A fully charged car gets a zero-length charging plan instead of done.

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

ROOT CAUSE

A zero energy request is not recognized as already satisfied.

THE FAILURE

A zero energy request is not recognized as already satisfied.

Unsuccessful approach: Requiring charger power first reports no-power for cars that need nothing.

Case contract

Minutes. The battery must receive need_wh; the charger draws rate_w at eff_pct percent efficiency, so duration = ceil(need_wh*6000/(rate_w*eff_pct)) minutes. Latest start = depart - buffer_min - duration, rounded down to a 15-minute boundary. If that is before now, start now with status 'late'. need_wh <= 0 returns [None, now, 'done']; rate_w or eff_pct <= 0 returns [None, None, 'no-power']. Return [start, finish, status].

Why this case matters

Depot, workplace and public EV chargers schedule sessions against prices, circuit limits and departure deadlines; a wrong decision silently strands a driver or overloads a feeder.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(now, depart, need_wh, rate_w, eff_pct, buffer_min):
    if need_wh < 0:
        return [None, now, 'done']
    if rate_w <= 0 or eff_pct <= 0:
        return [None, None, 'no-power']
    dur = -(-need_wh * 6000 // (rate_w * eff_pct))
    latest = depart - buffer_min - dur
    latest -= latest % 15
    if latest < now:
        return [now, now + dur, 'late']
    return [latest, latest + dur, 'ok']
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['boundary: nothing to charge', [100, 400, 0, 0, 90, 10], [None, 100, 'done']],
  ['boundary: latest start exactly now', [300, 390, 7400, 7400, 100, 0], [330, 390, 'ok']],
  ['boundary: no charger power', [100, 400, 5000, 0, 90, 10], [None, None, 'no-power']],
  ['regression: zero request handling', [37, 306, 0, 3700, 100, 15], [None, 37, 'done']],
  ['regression: zero request handling (partial repair)', [55, 571, 0, 0, 90, 10],
   [None, 55, 'done']],
  ['control 1', [117, 637, 11000, 11000, 95, 10], [555, 619, 'ok']],
  ['control 2', [448, 1142, 0, 3700, 85, 0], [None, 448, 'done']]],
 [['boundary: nothing to charge', [100, 400, 0, 0, 90, 10], [None, 100, 'done']],
  ['boundary: latest start exactly now', [300, 390, 7400, 7400, 100, 0], [330, 390, 'ok']],
  ['boundary: no charger power', [100, 400, 5000, 0, 90, 10], [None, None, 'no-power']],
  ['regression: zero request handling', [204, 654, 0, 3700, 100, 15], [None, 204, 'done']],
  ['regression: zero request handling (partial repair)', [318, 1160, 0, 0, 100, 30],
   [None, 318, 'done']],
  ['control 1', [416, 1003, 5000, 0, 85, 15], [None, None, 'no-power']],
  ['control 2', [221, 503, 5000, 0, 85, 30], [None, None, 'no-power']]],
 [['boundary: nothing to charge', [100, 400, 0, 0, 90, 10], [None, 100, 'done']],
  ['boundary: latest start exactly now', [300, 390, 7400, 7400, 100, 0], [330, 390, 'ok']],
  ['boundary: no charger power', [100, 400, 5000, 0, 90, 10], [None, None, 'no-power']],
  ['regression: zero request handling', [591, 1384, 0, 0, 90, 0], [None, 591, 'done']],
  ['regression: zero request handling (partial repair)', [504, 733, 0, 0, 85, 10],
   [None, 504, 'done']],
  ['control 1', [381, 632, 18000, 3700, 95, 30], [381, 689, 'late']],
  ['control 2', [19, 584, 30000, 11000, 90, 15], [375, 557, 'ok']]],
 [['boundary: nothing to charge', [100, 400, 0, 0, 90, 10], [None, 100, 'done']],
  ['boundary: latest start exactly now', [300, 390, 7400, 7400, 100, 0], [330, 390, 'ok']],
  ['boundary: no charger power', [100, 400, 5000, 0, 90, 10], [None, None, 'no-power']],
  ['regression: zero request handling', [474, 638, 0, 11000, 85, 15], [None, 474, 'done']],
  ['regression: zero request handling (partial repair)', [464, 1320, 0, 0, 100, 10],
   [None, 464, 'done']],
  ['control 1', [66, 229, 11000, 0, 90, 15], [None, None, 'no-power']],
  ['control 2', [44, 377, 2000, 0, 100, 0], [None, None, 'no-power']]],
 [['boundary: nothing to charge', [100, 400, 0, 0, 90, 10], [None, 100, 'done']],
  ['boundary: latest start exactly now', [300, 390, 7400, 7400, 100, 0], [330, 390, 'ok']],
  ['boundary: no charger power', [100, 400, 5000, 0, 90, 10], [None, None, 'no-power']],
  ['regression: zero request handling', [439, 470, 0, 7400, 90, 0], [None, 439, 'done']],
  ['regression: zero request handling (partial repair)', [41, 808, 0, 0, 95, 10],
   [None, 41, 'done']],
  ['control 1', [342, 397, 18000, 11000, 95, 10], [342, 446, 'late']],
  ['control 2', [577, 1400, 11000, 7400, 85, 15], [1275, 1380, 'ok']]]]
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 fixtureActualExpectedOutcome
boundary: nothing to charge[None, None, 'no-power'][None, 100, 'done']Failed
boundary: latest start exactly now[330, 390, 'ok'][330, 390, 'ok']Passed
boundary: no charger power[None, None, 'no-power'][None, None, 'no-power']Passed
regression: zero request handling[285, 285, 'ok'][None, 37, 'done']Failed
regression: zero request handling (partial repair)[None, None, 'no-power'][None, 55, 'done']Failed
control 1[555, 619, 'ok'][555, 619, 'ok']Passed
control 2[1140, 1140, 'ok'][None, 448, 'done']Failed

SHA-256 / 349fadd630691c2f079cfc95a1bff781c89e60a743963a2210d1c8333ed57517

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(now, depart, need_wh, rate_w, eff_pct, buffer_min):
    if need_wh <= 0 and rate_w > 0:
        return [None, now, 'done']
    if rate_w <= 0 or eff_pct <= 0:
        return [None, None, 'no-power']
    dur = -(-need_wh * 6000 // (rate_w * eff_pct))
    latest = depart - buffer_min - dur
    latest -= latest % 15
    if latest < now:
        return [now, now + dur, 'late']
    return [latest, latest + dur, 'ok']
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['boundary: nothing to charge', [100, 400, 0, 0, 90, 10], [None, 100, 'done']],
  ['boundary: latest start exactly now', [300, 390, 7400, 7400, 100, 0], [330, 390, 'ok']],
  ['boundary: no charger power', [100, 400, 5000, 0, 90, 10], [None, None, 'no-power']],
  ['regression: zero request handling', [37, 306, 0, 3700, 100, 15], [None, 37, 'done']],
  ['regression: zero request handling (partial repair)', [55, 571, 0, 0, 90, 10],
   [None, 55, 'done']],
  ['control 1', [117, 637, 11000, 11000, 95, 10], [555, 619, 'ok']],
  ['control 2', [448, 1142, 0, 3700, 85, 0], [None, 448, 'done']]],
 [['boundary: nothing to charge', [100, 400, 0, 0, 90, 10], [None, 100, 'done']],
  ['boundary: latest start exactly now', [300, 390, 7400, 7400, 100, 0], [330, 390, 'ok']],
  ['boundary: no charger power', [100, 400, 5000, 0, 90, 10], [None, None, 'no-power']],
  ['regression: zero request handling', [204, 654, 0, 3700, 100, 15], [None, 204, 'done']],
  ['regression: zero request handling (partial repair)', [318, 1160, 0, 0, 100, 30],
   [None, 318, 'done']],
  ['control 1', [416, 1003, 5000, 0, 85, 15], [None, None, 'no-power']],
  ['control 2', [221, 503, 5000, 0, 85, 30], [None, None, 'no-power']]],
 [['boundary: nothing to charge', [100, 400, 0, 0, 90, 10], [None, 100, 'done']],
  ['boundary: latest start exactly now', [300, 390, 7400, 7400, 100, 0], [330, 390, 'ok']],
  ['boundary: no charger power', [100, 400, 5000, 0, 90, 10], [None, None, 'no-power']],
  ['regression: zero request handling', [591, 1384, 0, 0, 90, 0], [None, 591, 'done']],
  ['regression: zero request handling (partial repair)', [504, 733, 0, 0, 85, 10],
   [None, 504, 'done']],
  ['control 1', [381, 632, 18000, 3700, 95, 30], [381, 689, 'late']],
  ['control 2', [19, 584, 30000, 11000, 90, 15], [375, 557, 'ok']]],
 [['boundary: nothing to charge', [100, 400, 0, 0, 90, 10], [None, 100, 'done']],
  ['boundary: latest start exactly now', [300, 390, 7400, 7400, 100, 0], [330, 390, 'ok']],
  ['boundary: no charger power', [100, 400, 5000, 0, 90, 10], [None, None, 'no-power']],
  ['regression: zero request handling', [474, 638, 0, 11000, 85, 15], [None, 474, 'done']],
  ['regression: zero request handling (partial repair)', [464, 1320, 0, 0, 100, 10],
   [None, 464, 'done']],
  ['control 1', [66, 229, 11000, 0, 90, 15], [None, None, 'no-power']],
  ['control 2', [44, 377, 2000, 0, 100, 0], [None, None, 'no-power']]],
 [['boundary: nothing to charge', [100, 400, 0, 0, 90, 10], [None, 100, 'done']],
  ['boundary: latest start exactly now', [300, 390, 7400, 7400, 100, 0], [330, 390, 'ok']],
  ['boundary: no charger power', [100, 400, 5000, 0, 90, 10], [None, None, 'no-power']],
  ['regression: zero request handling', [439, 470, 0, 7400, 90, 0], [None, 439, 'done']],
  ['regression: zero request handling (partial repair)', [41, 808, 0, 0, 95, 10],
   [None, 41, 'done']],
  ['control 1', [342, 397, 18000, 11000, 95, 10], [342, 446, 'late']],
  ['control 2', [577, 1400, 11000, 7400, 85, 15], [1275, 1380, 'ok']]]]
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 fixtureActualExpectedOutcome
boundary: nothing to charge[None, None, 'no-power'][None, 100, 'done']Failed
boundary: latest start exactly now[330, 390, 'ok'][330, 390, 'ok']Passed
boundary: no charger power[None, None, 'no-power'][None, None, 'no-power']Passed
regression: zero request handling[None, 37, 'done'][None, 37, 'done']Passed
regression: zero request handling (partial repair)[None, None, 'no-power'][None, 55, 'done']Failed
control 1[555, 619, 'ok'][555, 619, 'ok']Passed
control 2[None, 448, 'done'][None, 448, 'done']Passed

SHA-256 / 3ccbdc290e89e16eb7a155aa39153f78583f20e7736558d7c199caed8bc9392f

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 7 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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Verification & scope

Deterministic stipulated toy contract for teaching; no claim of conformance with any standard, vendor protocol or production controller. 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 2026-09-29T14:51:51.666509+00:00.

Case digest / 884b6d005266fb4e50af516856a68da3923b5435e37336757c30c5785dcc6626