Files
test-user f2fc5e09ab feat: SDXL default; AVIF/HEIF/JPEG-XL C2PA stripping
SD-1.5 dreamshaper at 768 px did not defeat SynthID v2 on Gemini 3 Pro
outputs (verified May 2026 via Gemini app's "Verify with SynthID"). Switch
the default invisible engine to SDXL at 1024 px, matching the raiw-app
production config (strength 0.05, steps 50). Drop the SD-1.5 pipeline.

Metadata layer: add C2PA UUID and IPTC AI marker byte-scan detection
across all formats, plus an ISOBMFF box walker (noai/isobmff.py) that
strips top-level C2PA uuid and JUMBF jumb boxes from AVIF/HEIF/JPEG-XL
containers without re-encoding.

README gets a Legal table and a Threat-model section about SynthID v2's
136-bit payload. CLAUDE.md tracks the SD-1.5 regression as historical
context.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-17 12:54:37 -07:00

220 lines
8.3 KiB
Python

"""Tests for AI metadata detection and removal."""
from __future__ import annotations
from pathlib import Path
from PIL import Image
from PIL.PngImagePlugin import PngInfo
from remove_ai_watermarks.metadata import (
_is_ai_key,
get_ai_metadata,
has_ai_metadata,
remove_ai_metadata,
)
# ── Key detection ───────────────────────────────────────────────────
class TestIsAiKey:
"""Tests for _is_ai_key helper."""
def test_exact_match_lowercase(self):
assert _is_ai_key("parameters")
def test_exact_match_mixed_case(self):
assert _is_ai_key("Parameters")
def test_keyword_substring(self):
assert _is_ai_key("stable_diffusion_model_v2")
def test_c2pa_detected(self):
assert _is_ai_key("c2pa_chunk")
def test_standard_key_not_flagged(self):
assert not _is_ai_key("Author")
def test_innocuous_key_not_flagged(self):
assert not _is_ai_key("Title")
def test_dpi_not_flagged(self):
assert not _is_ai_key("dpi")
# ── has_ai_metadata / get_ai_metadata ───────────────────────────────
class TestHasAiMetadata:
"""Tests for detecting AI metadata in images."""
def test_detects_ai_metadata(self, tmp_png_with_ai_metadata):
assert has_ai_metadata(tmp_png_with_ai_metadata)
def test_clean_image_no_ai(self, tmp_clean_png):
assert not has_ai_metadata(tmp_clean_png)
def test_detects_c2pa_uuid_in_isobmff_container(self, tmp_path: Path):
"""C2PA in AVIF/HEIF/MP4 lives in a ``uuid`` box identified by a fixed UUID.
Real AVIF/HEIF fixtures aren't shipped, so simulate the container by
prepending an ISOBMFF-shaped ftyp box and the C2PA UUID bytes.
"""
from remove_ai_watermarks.metadata import C2PA_UUID
path = tmp_path / "fake.avif"
# ftyp box: size(4) + 'ftyp' + 'avif' + minor_version(4) + 'avif'
ftyp = b"\x00\x00\x00\x18ftypavif\x00\x00\x00\x00avifmif1"
# uuid box: size(4) + 'uuid' + 16-byte UUID + minimal payload
uuid_box = b"\x00\x00\x00\x20uuid" + C2PA_UUID + b"jumb-payload"
path.write_bytes(ftyp + uuid_box + b"\x00" * 64)
assert has_ai_metadata(path)
def test_strip_c2pa_boxes_removes_uuid_box(self, tmp_path: Path):
"""ISOBMFF strip should drop the C2PA uuid box and keep everything else."""
from remove_ai_watermarks.metadata import C2PA_UUID
from remove_ai_watermarks.noai.isobmff import strip_c2pa_boxes
ftyp = b"\x00\x00\x00\x18ftypavif\x00\x00\x00\x00avifmif1"
# uuid box: size(4) + 'uuid' + 16-byte UUID + minimal payload (8 bytes -> total 32)
uuid_box = b"\x00\x00\x00\x20uuid" + C2PA_UUID + b"payload!"
mdat = b"\x00\x00\x00\x10mdat" + b"pixeldat"
cleaned, stripped = strip_c2pa_boxes(ftyp + uuid_box + mdat)
assert stripped == 1
assert cleaned == ftyp + mdat
def test_strip_c2pa_boxes_passthrough_for_non_isobmff(self):
"""Non-ISOBMFF input must be returned unchanged."""
from remove_ai_watermarks.noai.isobmff import strip_c2pa_boxes
data = b"\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR" + b"\x00" * 100
cleaned, stripped = strip_c2pa_boxes(data)
assert stripped == 0
assert cleaned == data
def test_remove_ai_metadata_strips_c2pa_in_avif(self, tmp_path: Path):
"""End-to-end: ``remove_ai_metadata`` on a fake .avif drops the C2PA box."""
from remove_ai_watermarks.metadata import C2PA_UUID, remove_ai_metadata
src = tmp_path / "in.avif"
ftyp = b"\x00\x00\x00\x18ftypavif\x00\x00\x00\x00avifmif1"
uuid_box = b"\x00\x00\x00\x20uuid" + C2PA_UUID + b"payload!"
mdat = b"\x00\x00\x00\x10mdat" + b"pixeldat"
src.write_bytes(ftyp + uuid_box + mdat)
out = tmp_path / "out.avif"
result = remove_ai_metadata(src, out)
assert result == out
assert out.read_bytes() == ftyp + mdat
# And after stripping, detection must no longer flag the cleaned file.
from remove_ai_watermarks.metadata import has_ai_metadata
assert not has_ai_metadata(out)
def test_detects_iptc_trained_algorithmic_media_marker(self, tmp_path: Path):
"""Some pipelines embed only the IPTC AI marker in XMP, no C2PA manifest."""
path = tmp_path / "fake.jpg"
# Minimal JPEG-ish bytes containing the IPTC AI marker in an XMP-like blob.
xmp = (
b"<x:xmpmeta><Iptc4xmpExt:DigitalSourceType>"
b"trainedAlgorithmicMedia"
b"</Iptc4xmpExt:DigitalSourceType></x:xmpmeta>"
)
path.write_bytes(b"\xff\xd8\xff\xe1" + xmp + b"\xff\xd9")
assert has_ai_metadata(path)
class TestGetAiMetadata:
"""Tests for extracting AI metadata."""
def test_extracts_parameters_key(self, tmp_png_with_ai_metadata):
meta = get_ai_metadata(tmp_png_with_ai_metadata)
assert "parameters" in meta
assert "Euler" in meta["parameters"]
def test_extracts_prompt_key(self, tmp_png_with_ai_metadata):
meta = get_ai_metadata(tmp_png_with_ai_metadata)
assert "prompt" in meta
def test_does_not_extract_author(self, tmp_png_with_ai_metadata):
meta = get_ai_metadata(tmp_png_with_ai_metadata)
assert "Author" not in meta
def test_clean_image_empty_dict(self, tmp_clean_png):
meta = get_ai_metadata(tmp_clean_png)
assert meta == {}
# ── remove_ai_metadata ──────────────────────────────────────────────
class TestRemoveAiMetadata:
"""Tests for stripping AI metadata."""
def test_removes_ai_keys(self, tmp_png_with_ai_metadata):
output = tmp_png_with_ai_metadata.parent / "cleaned.png"
remove_ai_metadata(tmp_png_with_ai_metadata, output)
with Image.open(output) as img:
assert "parameters" not in img.info
assert "prompt" not in img.info
def test_keeps_standard_metadata(self, tmp_png_with_ai_metadata):
output = tmp_png_with_ai_metadata.parent / "cleaned.png"
remove_ai_metadata(tmp_png_with_ai_metadata, output, keep_standard=True)
with Image.open(output) as img:
assert "Author" in img.info
assert img.info["Author"] == "Test Author"
def test_remove_all_metadata(self, tmp_png_with_ai_metadata):
output = tmp_png_with_ai_metadata.parent / "cleaned.png"
remove_ai_metadata(tmp_png_with_ai_metadata, output, keep_standard=False)
with Image.open(output) as img:
assert "Author" not in img.info
assert "parameters" not in img.info
def test_overwrite_in_place(self, tmp_path):
"""When output_path is None, should overwrite source."""
img = Image.new("RGB", (32, 32))
pnginfo = PngInfo()
pnginfo.add_text("parameters", "test data")
path = tmp_path / "inplace.png"
img.save(path, pnginfo=pnginfo)
result = remove_ai_metadata(path)
assert result == path
with Image.open(path) as cleaned:
assert "parameters" not in cleaned.info
def test_jpeg_output(self, tmp_path):
"""Test metadata removal for JPEG format."""
img = Image.new("RGB", (64, 64), color=(100, 150, 200))
pnginfo = PngInfo()
pnginfo.add_text("parameters", "test")
png_path = tmp_path / "source.png"
img.save(png_path, pnginfo=pnginfo)
jpg_path = tmp_path / "output.jpg"
result = remove_ai_metadata(png_path, jpg_path)
assert result == jpg_path
assert jpg_path.exists()
def test_creates_parent_directories(self, tmp_path):
img = Image.new("RGB", (32, 32))
pnginfo = PngInfo()
pnginfo.add_text("prompt", "test")
path = tmp_path / "source.png"
img.save(path, pnginfo=pnginfo)
output = tmp_path / "sub" / "dir" / "cleaned.png"
remove_ai_metadata(path, output)
assert output.exists()
def test_returns_path(self, tmp_clean_png):
output = tmp_clean_png.parent / "out.png"
result = remove_ai_metadata(tmp_clean_png, output)
assert isinstance(result, Path)
assert result == output