FAILURE MAP
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FA-84396 / Betting odds conversion / Open access

Upper-case odds text rejected · case 01

"EVS" and "2/1 ON" are rejected or mispriced.

Verified by executionVariant 1 · 11 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The text is not lower-cased before matching aliases and the suffix.

VERIFIED REPAIR

Lower-case before detecting the suffix and aliases.

Unsuccessful approach: Lower-casing after the suffix check still misses an upper-case " ON".

Case contract

Parse traditional fractional odds text, case-insensitively: "a/b" or "a-b" with positive integers, "evens"/"evs"/"even" for 1/1, and an optional trailing " on" meaning odds-on (the fraction is inverted, "2/1 on" = 1/2). Zero parts or anything else return "invalid". Return [decimal price rounded half up to two decimals, reduced profit fraction "a/b"].

Why this case matters

Racing feeds and manual price entry use traditional fractional notation with odds-on suffixes.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
import math
N = 1
observations = []
def solve(text):
    t = text.strip()
    on = t.endswith(' on')
    if on:
        t = t[:-3].strip()
    if t in ('evens', 'evs', 'even'):
        frac = Fraction(1)
    else:
        for sep in ('/', '-'):
            if sep in t:
                a, _, b = t.partition(sep)
                break
        else:
            return 'invalid'
        if not a.isdigit() or not b.isdigit() or int(b) == 0 or int(a) == 0:
            return 'invalid'
        frac = Fraction(int(a), int(b))
    if on:
        frac = 1 / frac
    dec = 1 + frac
    cents = math.floor(dec * 100 + Fraction(1, 2))
    return ['%d.%02d' % (cents // 100, cents % 100), '%d/%d' % (frac.numerator, frac.denominator)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
def run(args):
    try:
        return solve(*args)
    except Exception as exc:
        return 'raised ' + type(exc).__name__
cases = [[('control five to two', ('5/2',), ['3.50', '5/2']),
  ('control hyphen separator', ('11-4',), ['3.75', '11/4']),
  ('boundary evens alias', ('EVS',), ['2.00', '1/1']),
  ('boundary odds-on suffix', ('2/1 on',), ['1.50', '1/2']),
  ('boundary unreduced input', ('4/6',), ['1.67', '2/3']),
  ('boundary zero denominator', ('5/0',), 'invalid'),
  ('control half-up rounding', ('1/8',), ['1.13', '1/8']),
  ('regression: case normalization', ('EVS',), ['2.00', '1/1']),
  ('regression: case normalization', ('12/11 ON',), ['1.92', '11/12']),
  ('variant scenario 1', ('11/13',), ['1.85', '11/13']),
  ('variant scenario 2', ('18/1',), ['19.00', '18/1'])],
 [('control five to two', ('5/2',), ['3.50', '5/2']),
  ('control hyphen separator', ('11-4',), ['3.75', '11/4']),
  ('boundary evens alias', ('EVS',), ['2.00', '1/1']),
  ('boundary odds-on suffix', ('2/1 on',), ['1.50', '1/2']),
  ('boundary unreduced input', ('4/6',), ['1.67', '2/3']),
  ('boundary zero denominator', ('5/0',), 'invalid'),
  ('control half-up rounding', ('1/8',), ['1.13', '1/8']),
  ('regression: case normalization', ('Evens',), ['2.00', '1/1']),
  ('regression: case normalization', ('9/1 ON',), ['1.11', '1/9']),
  ('variant scenario 1', ('5/10',), ['1.50', '1/2']),
  ('variant scenario 2', ('16-5',), ['4.20', '16/5'])],
 [('control five to two', ('5/2',), ['3.50', '5/2']),
  ('control hyphen separator', ('11-4',), ['3.75', '11/4']),
  ('boundary evens alias', ('EVS',), ['2.00', '1/1']),
  ('boundary odds-on suffix', ('2/1 on',), ['1.50', '1/2']),
  ('boundary unreduced input', ('4/6',), ['1.67', '2/3']),
  ('boundary zero denominator', ('5/0',), 'invalid'),
  ('control half-up rounding', ('1/8',), ['1.13', '1/8']),
  ('regression: case normalization', ('Evens',), ['2.00', '1/1']),
  ('regression: case normalization', ('2/13 ON',), ['7.50', '13/2']),
  ('variant scenario 1', ('5/13 on',), ['3.60', '13/5']),
  ('variant scenario 2', ('13/4',), ['4.25', '13/4'])],
 [('control five to two', ('5/2',), ['3.50', '5/2']),
  ('control hyphen separator', ('11-4',), ['3.75', '11/4']),
  ('boundary evens alias', ('EVS',), ['2.00', '1/1']),
  ('boundary odds-on suffix', ('2/1 on',), ['1.50', '1/2']),
  ('boundary unreduced input', ('4/6',), ['1.67', '2/3']),
  ('boundary zero denominator', ('5/0',), 'invalid'),
  ('control half-up rounding', ('1/8',), ['1.13', '1/8']),
  ('regression: case normalization', ('16/10 ON',), ['1.63', '5/8']),
  ('variant scenario 1', ('2-1',), ['3.00', '2/1']),
  ('variant scenario 2', ('2/3',), ['1.67', '2/3'])],
 [('control five to two', ('5/2',), ['3.50', '5/2']),
  ('control hyphen separator', ('11-4',), ['3.75', '11/4']),
  ('boundary evens alias', ('EVS',), ['2.00', '1/1']),
  ('boundary odds-on suffix', ('2/1 on',), ['1.50', '1/2']),
  ('boundary unreduced input', ('4/6',), ['1.67', '2/3']),
  ('boundary zero denominator', ('5/0',), 'invalid'),
  ('control half-up rounding', ('1/8',), ['1.13', '1/8']),
  ('regression: case normalization', ('Evens',), ['2.00', '1/1']),
  ('regression: case normalization', ('7-2 ON',), ['1.29', '2/7']),
  ('variant scenario 1', ('13/2 on',), ['1.15', '2/13']),
  ('variant scenario 2', ('11/3',), ['4.67', '11/3'])]]
for label, args, expected in cases[N - 1]:
    check(label, run(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
control five to two['3.50', '5/2']['3.50', '5/2']Passed
control hyphen separator['3.75', '11/4']['3.75', '11/4']Passed
boundary evens aliasinvalid['2.00', '1/1']Failed
boundary odds-on suffix['1.50', '1/2']['1.50', '1/2']Passed
boundary unreduced input['1.67', '2/3']['1.67', '2/3']Passed
boundary zero denominatorinvalidinvalidPassed
control half-up rounding['1.13', '1/8']['1.13', '1/8']Passed
regression: case normalizationinvalid['2.00', '1/1']Failed
regression: case normalizationinvalid['1.92', '11/12']Failed
variant scenario 1['1.85', '11/13']['1.85', '11/13']Passed
variant scenario 2['19.00', '18/1']['19.00', '18/1']Passed

SHA-256 / 0c40df4cfac76f81633cf6d53a2b784d89a065bc72097b72414882e1d731a878

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
import math
N = 1
observations = []
def solve(text):
    on = text.strip().endswith(' on')
    t = text.strip().lower()
    if on:
        t = t[:-3].strip()
    if t in ('evens', 'evs', 'even'):
        frac = Fraction(1)
    else:
        for sep in ('/', '-'):
            if sep in t:
                a, _, b = t.partition(sep)
                break
        else:
            return 'invalid'
        if not a.isdigit() or not b.isdigit() or int(b) == 0 or int(a) == 0:
            return 'invalid'
        frac = Fraction(int(a), int(b))
    if on:
        frac = 1 / frac
    dec = 1 + frac
    cents = math.floor(dec * 100 + Fraction(1, 2))
    return ['%d.%02d' % (cents // 100, cents % 100), '%d/%d' % (frac.numerator, frac.denominator)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
def run(args):
    try:
        return solve(*args)
    except Exception as exc:
        return 'raised ' + type(exc).__name__
cases = [[('control five to two', ('5/2',), ['3.50', '5/2']),
  ('control hyphen separator', ('11-4',), ['3.75', '11/4']),
  ('boundary evens alias', ('EVS',), ['2.00', '1/1']),
  ('boundary odds-on suffix', ('2/1 on',), ['1.50', '1/2']),
  ('boundary unreduced input', ('4/6',), ['1.67', '2/3']),
  ('boundary zero denominator', ('5/0',), 'invalid'),
  ('control half-up rounding', ('1/8',), ['1.13', '1/8']),
  ('regression: case normalization', ('EVS',), ['2.00', '1/1']),
  ('regression: case normalization', ('12/11 ON',), ['1.92', '11/12']),
  ('variant scenario 1', ('11/13',), ['1.85', '11/13']),
  ('variant scenario 2', ('18/1',), ['19.00', '18/1'])],
 [('control five to two', ('5/2',), ['3.50', '5/2']),
  ('control hyphen separator', ('11-4',), ['3.75', '11/4']),
  ('boundary evens alias', ('EVS',), ['2.00', '1/1']),
  ('boundary odds-on suffix', ('2/1 on',), ['1.50', '1/2']),
  ('boundary unreduced input', ('4/6',), ['1.67', '2/3']),
  ('boundary zero denominator', ('5/0',), 'invalid'),
  ('control half-up rounding', ('1/8',), ['1.13', '1/8']),
  ('regression: case normalization', ('Evens',), ['2.00', '1/1']),
  ('regression: case normalization', ('9/1 ON',), ['1.11', '1/9']),
  ('variant scenario 1', ('5/10',), ['1.50', '1/2']),
  ('variant scenario 2', ('16-5',), ['4.20', '16/5'])],
 [('control five to two', ('5/2',), ['3.50', '5/2']),
  ('control hyphen separator', ('11-4',), ['3.75', '11/4']),
  ('boundary evens alias', ('EVS',), ['2.00', '1/1']),
  ('boundary odds-on suffix', ('2/1 on',), ['1.50', '1/2']),
  ('boundary unreduced input', ('4/6',), ['1.67', '2/3']),
  ('boundary zero denominator', ('5/0',), 'invalid'),
  ('control half-up rounding', ('1/8',), ['1.13', '1/8']),
  ('regression: case normalization', ('Evens',), ['2.00', '1/1']),
  ('regression: case normalization', ('2/13 ON',), ['7.50', '13/2']),
  ('variant scenario 1', ('5/13 on',), ['3.60', '13/5']),
  ('variant scenario 2', ('13/4',), ['4.25', '13/4'])],
 [('control five to two', ('5/2',), ['3.50', '5/2']),
  ('control hyphen separator', ('11-4',), ['3.75', '11/4']),
  ('boundary evens alias', ('EVS',), ['2.00', '1/1']),
  ('boundary odds-on suffix', ('2/1 on',), ['1.50', '1/2']),
  ('boundary unreduced input', ('4/6',), ['1.67', '2/3']),
  ('boundary zero denominator', ('5/0',), 'invalid'),
  ('control half-up rounding', ('1/8',), ['1.13', '1/8']),
  ('regression: case normalization', ('16/10 ON',), ['1.63', '5/8']),
  ('variant scenario 1', ('2-1',), ['3.00', '2/1']),
  ('variant scenario 2', ('2/3',), ['1.67', '2/3'])],
 [('control five to two', ('5/2',), ['3.50', '5/2']),
  ('control hyphen separator', ('11-4',), ['3.75', '11/4']),
  ('boundary evens alias', ('EVS',), ['2.00', '1/1']),
  ('boundary odds-on suffix', ('2/1 on',), ['1.50', '1/2']),
  ('boundary unreduced input', ('4/6',), ['1.67', '2/3']),
  ('boundary zero denominator', ('5/0',), 'invalid'),
  ('control half-up rounding', ('1/8',), ['1.13', '1/8']),
  ('regression: case normalization', ('Evens',), ['2.00', '1/1']),
  ('regression: case normalization', ('7-2 ON',), ['1.29', '2/7']),
  ('variant scenario 1', ('13/2 on',), ['1.15', '2/13']),
  ('variant scenario 2', ('11/3',), ['4.67', '11/3'])]]
for label, args, expected in cases[N - 1]:
    check(label, run(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
control five to two['3.50', '5/2']['3.50', '5/2']Passed
control hyphen separator['3.75', '11/4']['3.75', '11/4']Passed
boundary evens alias['2.00', '1/1']['2.00', '1/1']Passed
boundary odds-on suffix['1.50', '1/2']['1.50', '1/2']Passed
boundary unreduced input['1.67', '2/3']['1.67', '2/3']Passed
boundary zero denominatorinvalidinvalidPassed
control half-up rounding['1.13', '1/8']['1.13', '1/8']Passed
regression: case normalization['2.00', '1/1']['2.00', '1/1']Passed
regression: case normalizationinvalid['1.92', '11/12']Failed
variant scenario 1['1.85', '11/13']['1.85', '11/13']Passed
variant scenario 2['19.00', '18/1']['19.00', '18/1']Passed

SHA-256 / fab7f37c3d4a9ac73adce8d63d56cd2c946bae1ac519add8f6a1c7526ecbd9a0

3 / The verified repair

Exit 0
"""Failure Map reference implementation. Python standard library only."""
import json
from fractions import Fraction
import math
N = 1
observations = []
def solve(text):
    t = text.strip().lower()
    on = t.endswith(' on')
    if on:
        t = t[:-3].strip()
    if t in ('evens', 'evs', 'even'):
        frac = Fraction(1)
    else:
        for sep in ('/', '-'):
            if sep in t:
                a, _, b = t.partition(sep)
                break
        else:
            return 'invalid'
        if not a.isdigit() or not b.isdigit() or int(b) == 0 or int(a) == 0:
            return 'invalid'
        frac = Fraction(int(a), int(b))
    if on:
        frac = 1 / frac
    dec = 1 + frac
    cents = math.floor(dec * 100 + Fraction(1, 2))
    return ['%d.%02d' % (cents // 100, cents % 100), '%d/%d' % (frac.numerator, frac.denominator)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
def run(args):
    try:
        return solve(*args)
    except Exception as exc:
        return 'raised ' + type(exc).__name__
cases = [[('control five to two', ('5/2',), ['3.50', '5/2']),
  ('control hyphen separator', ('11-4',), ['3.75', '11/4']),
  ('boundary evens alias', ('EVS',), ['2.00', '1/1']),
  ('boundary odds-on suffix', ('2/1 on',), ['1.50', '1/2']),
  ('boundary unreduced input', ('4/6',), ['1.67', '2/3']),
  ('boundary zero denominator', ('5/0',), 'invalid'),
  ('control half-up rounding', ('1/8',), ['1.13', '1/8']),
  ('regression: case normalization', ('EVS',), ['2.00', '1/1']),
  ('regression: case normalization', ('12/11 ON',), ['1.92', '11/12']),
  ('variant scenario 1', ('11/13',), ['1.85', '11/13']),
  ('variant scenario 2', ('18/1',), ['19.00', '18/1'])],
 [('control five to two', ('5/2',), ['3.50', '5/2']),
  ('control hyphen separator', ('11-4',), ['3.75', '11/4']),
  ('boundary evens alias', ('EVS',), ['2.00', '1/1']),
  ('boundary odds-on suffix', ('2/1 on',), ['1.50', '1/2']),
  ('boundary unreduced input', ('4/6',), ['1.67', '2/3']),
  ('boundary zero denominator', ('5/0',), 'invalid'),
  ('control half-up rounding', ('1/8',), ['1.13', '1/8']),
  ('regression: case normalization', ('Evens',), ['2.00', '1/1']),
  ('regression: case normalization', ('9/1 ON',), ['1.11', '1/9']),
  ('variant scenario 1', ('5/10',), ['1.50', '1/2']),
  ('variant scenario 2', ('16-5',), ['4.20', '16/5'])],
 [('control five to two', ('5/2',), ['3.50', '5/2']),
  ('control hyphen separator', ('11-4',), ['3.75', '11/4']),
  ('boundary evens alias', ('EVS',), ['2.00', '1/1']),
  ('boundary odds-on suffix', ('2/1 on',), ['1.50', '1/2']),
  ('boundary unreduced input', ('4/6',), ['1.67', '2/3']),
  ('boundary zero denominator', ('5/0',), 'invalid'),
  ('control half-up rounding', ('1/8',), ['1.13', '1/8']),
  ('regression: case normalization', ('Evens',), ['2.00', '1/1']),
  ('regression: case normalization', ('2/13 ON',), ['7.50', '13/2']),
  ('variant scenario 1', ('5/13 on',), ['3.60', '13/5']),
  ('variant scenario 2', ('13/4',), ['4.25', '13/4'])],
 [('control five to two', ('5/2',), ['3.50', '5/2']),
  ('control hyphen separator', ('11-4',), ['3.75', '11/4']),
  ('boundary evens alias', ('EVS',), ['2.00', '1/1']),
  ('boundary odds-on suffix', ('2/1 on',), ['1.50', '1/2']),
  ('boundary unreduced input', ('4/6',), ['1.67', '2/3']),
  ('boundary zero denominator', ('5/0',), 'invalid'),
  ('control half-up rounding', ('1/8',), ['1.13', '1/8']),
  ('regression: case normalization', ('16/10 ON',), ['1.63', '5/8']),
  ('variant scenario 1', ('2-1',), ['3.00', '2/1']),
  ('variant scenario 2', ('2/3',), ['1.67', '2/3'])],
 [('control five to two', ('5/2',), ['3.50', '5/2']),
  ('control hyphen separator', ('11-4',), ['3.75', '11/4']),
  ('boundary evens alias', ('EVS',), ['2.00', '1/1']),
  ('boundary odds-on suffix', ('2/1 on',), ['1.50', '1/2']),
  ('boundary unreduced input', ('4/6',), ['1.67', '2/3']),
  ('boundary zero denominator', ('5/0',), 'invalid'),
  ('control half-up rounding', ('1/8',), ['1.13', '1/8']),
  ('regression: case normalization', ('Evens',), ['2.00', '1/1']),
  ('regression: case normalization', ('7-2 ON',), ['1.29', '2/7']),
  ('variant scenario 1', ('13/2 on',), ['1.15', '2/13']),
  ('variant scenario 2', ('11/3',), ['4.67', '11/3'])]]
for label, args, expected in cases[N - 1]:
    check(label, run(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
control five to two['3.50', '5/2']['3.50', '5/2']Passed
control hyphen separator['3.75', '11/4']['3.75', '11/4']Passed
boundary evens alias['2.00', '1/1']['2.00', '1/1']Passed
boundary odds-on suffix['1.50', '1/2']['1.50', '1/2']Passed
boundary unreduced input['1.67', '2/3']['1.67', '2/3']Passed
boundary zero denominatorinvalidinvalidPassed
control half-up rounding['1.13', '1/8']['1.13', '1/8']Passed
regression: case normalization['2.00', '1/1']['2.00', '1/1']Passed
regression: case normalization['1.92', '11/12']['1.92', '11/12']Passed
variant scenario 1['1.85', '11/13']['1.85', '11/13']Passed
variant scenario 2['19.00', '18/1']['19.00', '18/1']Passed

SHA-256 / 2664aa351b96c645ce361d64a5b1b53aca563bdedfa554e909b50f222595976e

Verification & scope

Stipulated, bounded toy contract stated in the contract field; not a claim of conformance with any operator, exchange or regulator rule set. 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 2026-09-29T14:50:30.508592+00:00.

Case digest / 38c6252f1a4e6ce23fdef3295080072dd7dc9e5670ea77e67024cff1e2ea3171