FA-2901 / Unicode / Open access

A titlecase digraph is reduced to an uppercase digraph · case 01

A titlecase digraph is reduced to an uppercase digraph.

Verified by executionVariant 1 · 4 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The implementation applies an operation whose text or grammar semantics violate this contract: Titlecase every word using Unicode titlecase mappings.

VERIFIED REPAIR

Implement the complete stated contract, including the boundary fixtures: Titlecase every word using Unicode titlecase mappings.

Unsuccessful approach: The attempted repair handles the primary example but still violates a separate boundary of the same contract.

Case contract

Titlecase every word using Unicode titlecase mappings.

Why this case matters

A local executable model for consumers of structured text; oracle values are authored literals, not outputs copied from the repaired implementation.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import re, unicodedata, json, csv, io, html, base64, binascii, codecs, struct
from urllib.parse import quote, unquote, unquote_to_bytes, urlencode, parse_qsl, urlsplit, urlunsplit
from email.header import decode_header, make_header
from email.utils import getaddresses
from xml.etree import ElementTree as ET
import shlex, string, textwrap

N = 1
observations = []
def solve(x):
    try:
        return x.upper()
    except Exception as exc:
        return {"error": type(exc).__name__}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('boundary 1', solve('ǳuro'), 'ǲuro')
check('boundary 2', solve("they're"), "They'Re")
check('boundary 3', solve('hello-world'), 'Hello-World')
check('boundary 4', solve(''), '')
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
boundary 1	`ǱURO`	`ǲuro`	Failed
boundary 2	`THEY'RE`	`They'Re`	Failed
boundary 3	`HELLO-WORLD`	`Hello-World`	Failed
boundary 4			Passed

SHA-256 / 533f326946beb214e03105f2c5e6ad979256813f4ca8013824bb18f8f8b114d1

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import re, unicodedata, json, csv, io, html, base64, binascii, codecs, struct
from urllib.parse import quote, unquote, unquote_to_bytes, urlencode, parse_qsl, urlsplit, urlunsplit
from email.header import decode_header, make_header
from email.utils import getaddresses
from xml.etree import ElementTree as ET
import shlex, string, textwrap

N = 1
observations = []
def solve(x):
    try:
        return ' '.join(w.capitalize() for w in x.split(' '))
    except Exception as exc:
        return {"error": type(exc).__name__}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('boundary 1', solve('ǳuro'), 'ǲuro')
check('boundary 2', solve("they're"), "They'Re")
check('boundary 3', solve('hello-world'), 'Hello-World')
check('boundary 4', solve(''), '')
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
boundary 1	`ǲuro`	`ǲuro`	Passed
boundary 2	`They're`	`They'Re`	Failed
boundary 3	`Hello-world`	`Hello-World`	Failed
boundary 4			Passed

SHA-256 / af26d1d550ed83369fccef9f62e1faa320b177aa000b71e6d785ebe2d73f1fa5

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import re, unicodedata, json, csv, io, html, base64, binascii, codecs, struct
from urllib.parse import quote, unquote, unquote_to_bytes, urlencode, parse_qsl, urlsplit, urlunsplit
from email.header import decode_header, make_header
from email.utils import getaddresses
from xml.etree import ElementTree as ET
import shlex, string, textwrap

N = 1
observations = []
def solve(x):
    try:
        return x.title()
    except Exception as exc:
        return {"error": type(exc).__name__}
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('boundary 1', solve('ǳuro'), 'ǲuro')
check('boundary 2', solve("they're"), "They'Re")
check('boundary 3', solve('hello-world'), 'Hello-World')
check('boundary 4', solve(''), '')
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
boundary 1	`ǲuro`	`ǲuro`	Passed
boundary 2	`They'Re`	`They'Re`	Passed
boundary 3	`Hello-World`	`Hello-World`	Passed
boundary 4			Passed

SHA-256 / 078e76a39634fc3520dbebcf030bd645d03545f2499edfaf2e73a46f5881ac9f

Verification & scope

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 2026-09-29T14:37:18.804622+00:00.

Case digest / 137e555f8306d13e2c39308c0c95eb34ed262277a10aada25c2101e7218d5e92