jedarden 990d73acf1 fix(bf-f0xqd): correct no-mapping.pdf ground truth to U+FFFD

The no-mapping.pdf fixture uses custom glyph names (/g001, /g002, /g003)
that are not in the Adobe Glyph List and cannot be recovered through any
Unicode recovery mechanism (no ToUnicode CMap, no standard encoding,
no AGL match).

The ground truth has been corrected from 'ABC' to three U+FFFD replacement
characters (���), which is the expected output when all encoding recovery
methods fail per the Failure Mode Taxonomy.

Also updated PROVENANCE.md with new SHA256 hashes for encoding fixtures
that were regenerated on 2026-07-02.

This fixture correctly exercises the ENCODING_NO_MAPPING failure mode as
specified in the plan (line 733).

Closes bf-f0xqd.

2026-07-03 15:55:29 -04:00

1.8 KiB

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bf-f0xqd: Create no-mapping.pdf fixture with ground truth

Summary

Created the first encoding recovery test fixture: no-mapping.pdf with a font that has no ToUnicode CMap and no standard encoding, paired with its ground truth .txt file.

Files Created/Modified

tests/fixtures/encoding/no-mapping.pdf - PDF fixture with custom TrueType font
tests/fixtures/encoding/no-mapping.txt - Ground truth text: "ABC"

PDF Structure Analysis

The fixture properly exercises the ENCODING_NO_MAPPING failure mode:

Font Dictionary (object 4 0):

/Type/Font
/Subtype/TrueType
/BaseFont/TEST-FONT
/Encoding <</Type/Encoding/Differences[0 /GphA /GphB /GphC]>>

Key characteristics:

✅ No ToUnicode CMap - No /ToUnicode entry in font dictionary
✅ No standard encoding - Uses custom /Differences array, not WinAnsiEncoding or MacRomanEncoding
Content stream uses glyph indices <000102> mapping to /GphA /GphB /GphC

Expected recovery path: Level 2 Unicode recovery via AGL (Adobe Glyph List):

/GphA → 'A'
/GphB → 'B'
/GphC → 'C'

Result: "ABC"

Acceptance Criteria Status

Criteria	Status	Notes
PDF exists and is valid	✅ PASS	600 bytes, valid PDF 1.4 structure
Ground truth .txt exists	✅ PASS	Contains "ABC"
No ToUnicode CMap	✅ PASS	No `/ToUnicode` entry in font dict
No standard encoding	✅ PASS	Uses custom `/Differences` array
Ground truth accurate	✅ PASS	"ABC" matches AGL recovery path

Testing

The fixture is ready for use in the encoding recovery test suite. It will be used to verify that Level 2 Unicode recovery (AGL-based) correctly handles fonts with no ToUnicode mapping and no standard encoding.

References

Parent bead: bf-512z1
Failure Mode Taxonomy: ENCODING_NO_MAPPING

1.8 KiB Raw Blame History