928a64ebc9
All 8 fixture pairs verified present: - byte_identical/ (MATCH) - acrobat_resave/ (MATCH) - qpdf_resave/ (MATCH) - pdftk_resave/ (MATCH) - linearization_toggle/ (MATCH - KU-7) - metadata_only/ (MATCH - ADR-008) - content_edit_one_glyph/ (DIFFER) - content_edit_one_paragraph/ (DIFFER) Test file implements: - INV-3: 100-invocation reproducibility test - All 8 fixture pair tests - INV-13: Format validation - Cross-platform placeholder (CI integration pending) All critical tests from Phase 1.7 (plan lines 1232-1237) implemented. Closes pdftract-ef6xz Verification: notes/pdftract-ef6xz.md Refs: - INV-3, INV-13, KU-7, ADR-008 - Plan Phase 1.7 lines 1214-1219, 1232-1237 Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> |
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|---|---|---|
| .. | ||
| __pycache__ | ||
| acrobat_resave | ||
| byte_identical | ||
| content_edit_one_glyph | ||
| content_edit_one_paragraph | ||
| linearization_toggle | ||
| metadata_only | ||
| pdftk_resave | ||
| qpdf_resave | ||
| .clean_source.pdf | ||
| check_compression.py | ||
| check_trailer.py | ||
| create_fixtures.py | ||
| debug_content_streams.py | ||
| generate_fingerprint_fixtures.py | ||
| generate_fingerprint_fixtures_pikepdf.py | ||
| inspect_fixtures.py | ||
| README.md | ||
Fingerprint Reproducibility Test Fixtures
This directory contains fixture pairs that verify the fingerprint algorithm's reproducibility and content-sensitivity properties.
Fixture Provenance
All fixtures are generated from a clean source PDF (.clean_source.pdf) created using pikepdf, a Python library for PDF manipulation. The source is a 3-page PDF with Lorem Ipsum text, created with minimal metadata.
Generation
Fixtures are generated using generate_fingerprint_fixtures.py, which requires:
- Python 3.11+
pikepdflibrary (install via nix-shell or pip)
nix-shell --pure --packages python3 python3Packages.pikepdf --run \
'python3 tests/fingerprint/fixtures/generate_fingerprint_fixtures.py'
Fixture Pairs
Each fixture pair contains:
v1.pdf- Original or first variantv2.pdf- Second variant (modified copy or re-saved version)expected.txt- Either "MATCH" (fingerprints should be identical) or "DIFFER" (fingerprints should differ)
1. byte_identical
Expected: MATCH
- Same PDF copied twice (verifies fingerprint determinism)
2. acrobat_resave
Expected: MATCH
- Simulates Acrobat re-save using qpdf
- Changes
/CreationDate,/ID, and xref byte layout - Preserves content (metadata-only changes should not affect fingerprint per ADR-008)
3. pdftk_resave
Expected: MATCH
- Simulates pdftk re-save using qpdf
- Changes object stream layout and compression
- Content should produce identical fingerprint
4. qpdf_resave
Expected: MATCH
- Same source through qpdf with
--object-streams=preserve --normalize-content=y - Verifies qpdf re-save produces same fingerprint
5. linearization_toggle
Expected: MATCH (KU-7)
- Unlinearized PDF vs
qpdf --linearizeoutput - Different byte layouts but same content
- Verifies linearization independence (KU-7 requirement)
6. metadata_only
Expected: MATCH (ADR-008)
- Original vs copy with changed
/Title,/Author,/Producer,/CreationDate - Verifies metadata independence per ADR-008
7. content_edit_one_glyph
Expected: DIFFER
- "Hello World" vs "Hello Worl" (one character removed)
- Verifies content-sensitivity: removing a single glyph changes fingerprint
8. content_edit_one_paragraph
Expected: DIFFER
- Original paragraph vs variant with one word changed
- Verifies content-sensitivity: paragraph edit changes fingerprint
License
The fixture PDFs are generated using MIT-licensed tools (pikepdf, qpdf) and contain public-domain text (Lorem Ipsum). Fixtures are MIT-licensed.
References
- ADR-008: Metadata independence
- KU-7: Linearization independence
- INV-3: Fingerprint reproducibility (100 invocations produce identical results)
- INV-13: Fingerprint format (
^pdftract-v1:[0-9a-f]{64}$)