Files
remove-ai-watermarks/tests/test_identify.py
T
test-user ad3b8ee248 feat(identify): read EXIF Software / XMP CreatorTool generator tags
Closes the documented gap where EXIF/XMP fields inside AVIF/HEIF/JXL went
unparsed. metadata.exif_generator extracts the EXIF Software/Artist tag
(via PIL+piexif, which opens AVIF natively) and the XMP CreatorTool (via a
container-agnostic raw-byte scan that also covers HEIF/JXL that PIL can't
open), and matches against AI_GENERATOR_TOKENS so only generator names
(Firefly, DALL-E, Midjourney, ComfyUI, ...) fire -- a plain 'Adobe
Photoshop' or 'GIMP' tag is not flagged.

identify() surfaces it as a high-confidence signal and uses it for
platform attribution when no C2PA names a platform, so an AVIF/HEIF whose
only AI signal is an EXIF/XMP generator tag is now caught.

Validated with synthesized fixtures (the 'no positive fixtures' blocker
was self-imposed): real AVIF and JPEG written with EXIF Software via PIL,
plus an XMP CreatorTool raw-scan fixture. Zero false positives across the
109-image corpus (real iPhone photos carry no AI generator token).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-24 17:56:39 -07:00

320 lines
13 KiB
Python

"""Tests for the provenance identifier (identify.py).
Pure attribution logic is unit-tested directly; end-to-end verdicts assert
against the real committed C2PA / IPTC fixtures in data/samples/.
"""
from __future__ import annotations
import json
from dataclasses import asdict
from pathlib import Path
from unittest.mock import patch
import pytest
from remove_ai_watermarks.identify import (
ProvenanceReport,
_ai_tools_in,
_attribute_platform,
_issuers_in,
identify,
)
# Where the lazy import inside identify._visible_sparkle resolves the detector.
_SPARKLE_TARGET = "remove_ai_watermarks.gemini_engine.detect_sparkle_confidence"
SAMPLES_DIR = Path(__file__).resolve().parent.parent / "data" / "samples"
# ── Pure attribution logic (no file IO) ─────────────────────────────
class TestAttributePlatform:
def test_openai(self):
assert "OpenAI" in (_attribute_platform(["OpenAI"]) or "")
def test_designer_wins_over_openai_backend(self):
# Microsoft Designer signs as "OpenAI, Microsoft"; name the product.
platform = _attribute_platform(["OpenAI", "Microsoft"])
assert platform
assert "Designer" in platform
def test_adobe(self):
assert _attribute_platform(["Adobe"]) == "Adobe Firefly"
def test_google(self):
assert "Google" in (_attribute_platform(["Google LLC"]) or "")
def test_truepic_is_signer_not_generator(self):
platform = _attribute_platform(["Truepic"])
assert platform
assert "signer" in platform.lower()
def test_microsoft_label_is_model_neutral(self):
# Bing now runs MAI-Image, not DALL-E; the label must not claim DALL-E.
platform = _attribute_platform(["Microsoft"])
assert platform
assert "DALL-E" not in platform
def test_stability(self):
platform = _attribute_platform(["Stability AI"])
assert platform
assert "Stability AI" in platform
def test_empty_is_none(self):
assert _attribute_platform([]) is None
class TestIssuersIn:
def test_finds_openai(self):
assert _issuers_in(b"...OpenAI...trainedAlgorithmicMedia") == ["OpenAI"]
def test_finds_multiple_sorted(self):
assert _issuers_in(b"Microsoft and OpenAI") == ["Microsoft", "OpenAI"]
def test_none_present(self):
assert _issuers_in(b"just some bytes") == []
class TestAiToolsIn:
def test_finds_generator(self):
assert _ai_tools_in(b"...claim_generator Imagen 3...") == ["Imagen"]
def test_none_present(self):
assert _ai_tools_in(b"a regular photo, no tools") == []
class TestIdentifyNonPng:
"""Non-PNG containers (JPEG/WebP/AVIF) carry C2PA where the caBX parser can't
reach; identify recovers issuer + generator via the binary scan. Synthetic
byte blobs mirror tests/test_metadata.py::TestSynthIDSourceNonPng.
"""
def _c2pa_jpeg(self, tmp_path: Path, blob: bytes) -> Path:
path = tmp_path / "img.jpg"
path.write_bytes(b"\xff\xd8\xff\xe1jumbc2pa" + blob + b"\xff\xd9")
return path
def test_google_imagen_jpeg(self, tmp_path: Path):
path = self._c2pa_jpeg(tmp_path, b"Google Imagen ... trainedAlgorithmicMedia")
r = identify(path, check_visible=False)
assert r.is_ai_generated is True
assert r.platform is not None
assert "Google" in r.platform
# Generator recovered from the non-PNG blob shows up in the c2pa signal.
c2pa_signal = next(s for s in r.signals if s.name == "c2pa")
assert "Imagen" in c2pa_signal.detail
def test_openai_jpeg_has_synthid(self, tmp_path: Path):
path = self._c2pa_jpeg(tmp_path, b"OpenAI DALL-E ... trainedAlgorithmicMedia")
r = identify(path, check_visible=False)
assert any("SynthID" in w for w in r.watermarks)
def test_stability_ai_issuer_attributed_no_synthid(self, tmp_path: Path):
path = self._c2pa_jpeg(tmp_path, b"Stability AI ... trainedAlgorithmicMedia")
r = identify(path, check_visible=False)
assert r.is_ai_generated is True
assert r.platform is not None
assert "Stability AI" in r.platform
assert not any("SynthID" in w for w in r.watermarks) # Stability does not use SynthID
def test_c2pa_without_ai_marker_is_unknown(self, tmp_path: Path):
# Adobe signs C2PA on plain Photoshop edits too. Without an AI digital-
# source marker, the honest verdict is unknown -- the C2PA watermark is
# still listed, but is_ai_generated is not asserted True.
path = self._c2pa_jpeg(tmp_path, b"Adobe ... no ai marker here")
r = identify(path, check_visible=False)
assert r.is_ai_generated is None
assert any("C2PA" in w for w in r.watermarks)
assert not any("SynthID" in w for w in r.watermarks)
# ── End-to-end verdicts on real fixtures ────────────────────────────
@pytest.mark.skipif(not SAMPLES_DIR.exists(), reason="data/samples not present")
class TestIdentifyRealSamples:
def test_openai_chatgpt(self):
r = identify(SAMPLES_DIR / "chatgpt-1.png", check_visible=False)
assert r.is_ai_generated is True
assert r.confidence == "high"
assert r.platform
assert "OpenAI" in r.platform
assert any("C2PA" in w for w in r.watermarks)
assert any("SynthID" in w for w in r.watermarks)
def test_adobe_firefly_has_no_synthid(self):
r = identify(SAMPLES_DIR / "firefly-1.png", check_visible=False)
assert r.is_ai_generated is True
assert r.platform == "Adobe Firefly"
assert not any("SynthID" in w for w in r.watermarks)
def test_iptc_made_with_ai(self):
# mj-1.png carries the IPTC digitalSourceType "Made with AI" marker.
r = identify(SAMPLES_DIR / "mj-1.png", check_visible=False)
assert r.is_ai_generated is True
assert any("IPTC" in w for w in r.watermarks)
def test_clean_photo_is_unknown_not_clean(self):
r = identify(SAMPLES_DIR / "not-ai-1.jpeg", check_visible=False)
assert r.is_ai_generated is None # never asserted False
assert r.platform is None
assert r.confidence == "none"
assert r.watermarks == []
def test_strip_caveat_always_present(self):
r = identify(SAMPLES_DIR / "not-ai-1.jpeg", check_visible=False)
assert any("not proof" in c for c in r.caveats)
def test_returns_report_dataclass(self):
assert isinstance(identify(SAMPLES_DIR / "firefly-1.png", check_visible=False), ProvenanceReport)
# ── Local diffusion parameters (Stable Diffusion / ComfyUI) ─────────
class TestIdentifyLocalParams:
"""A PNG carrying SD-style generation params is attributed to a local pipeline."""
def test_sd_params_attributed_to_local_pipeline(self, tmp_png_with_ai_metadata: Path):
r = identify(tmp_png_with_ai_metadata, check_visible=False)
assert r.is_ai_generated is True
assert r.confidence == "high"
assert r.platform is not None
assert "Stable Diffusion" in r.platform
assert any("generation parameters" in w for w in r.watermarks)
def test_gen_params_signal_lists_keys(self, tmp_png_with_ai_metadata: Path):
r = identify(tmp_png_with_ai_metadata, check_visible=False)
signal = next(s for s in r.signals if s.name == "gen_params")
assert "parameters" in signal.detail
assert signal.confidence == "high"
def test_clean_png_is_unknown(self, tmp_clean_png: Path):
r = identify(tmp_clean_png, check_visible=False)
assert r.is_ai_generated is None
assert r.platform is None
assert r.confidence == "none"
assert r.signals == []
# ── Visible-sparkle fallback (mocked detector) ──────────────────────
class TestIdentifyVisibleSparkle:
"""The visible-sparkle signal gates on the corpus-tuned threshold (0.5)."""
def test_above_threshold_promotes_to_medium(self, tmp_clean_png: Path):
with patch(_SPARKLE_TARGET, return_value=0.7):
r = identify(tmp_clean_png, check_visible=True)
assert r.is_ai_generated is True
assert r.confidence == "medium"
assert r.platform is not None
assert "Gemini" in r.platform
signal = next(s for s in r.signals if s.name == "visible_sparkle")
assert signal.confidence == "medium"
def test_below_threshold_not_promoted(self, tmp_clean_png: Path):
with patch(_SPARKLE_TARGET, return_value=0.4):
r = identify(tmp_clean_png, check_visible=True)
assert r.is_ai_generated is None
assert not any(s.name == "visible_sparkle" for s in r.signals)
def test_detector_unavailable_does_not_crash(self, tmp_clean_png: Path):
with patch(_SPARKLE_TARGET, return_value=None):
r = identify(tmp_clean_png, check_visible=True)
assert r.is_ai_generated is None
assert not any(s.name == "visible_sparkle" for s in r.signals)
def test_check_visible_false_skips_detector(self, tmp_clean_png: Path):
# Even a strong detection is ignored when the caller opts out.
with patch(_SPARKLE_TARGET, return_value=0.99) as mock_detect:
r = identify(tmp_clean_png, check_visible=False)
mock_detect.assert_not_called()
assert not any(s.name == "visible_sparkle" for s in r.signals)
def test_metadata_keeps_high_even_with_sparkle(self, tmp_png_with_ai_metadata: Path):
# Metadata verdict (high) is not downgraded by an additional sparkle hit.
with patch(_SPARKLE_TARGET, return_value=0.7):
r = identify(tmp_png_with_ai_metadata, check_visible=True)
assert r.confidence == "high"
# ── Caveats and serialization ───────────────────────────────────────
@pytest.mark.skipif(not SAMPLES_DIR.exists(), reason="data/samples not present")
class TestIdentifyCaveats:
def test_openai_hedge_caveat_present(self):
r = identify(SAMPLES_DIR / "chatgpt-1.png", check_visible=False)
assert any("before the rollout" in c for c in r.caveats)
def test_synthid_proxy_caveat_present(self):
r = identify(SAMPLES_DIR / "chatgpt-1.png", check_visible=False)
assert any("not locally" in c for c in r.caveats)
def test_caveats_are_deduplicated(self):
r = identify(SAMPLES_DIR / "chatgpt-1.png", check_visible=False)
assert len(r.caveats) == len(set(r.caveats))
class TestReportSerializable:
def test_report_is_json_serializable(self, tmp_png_with_ai_metadata: Path):
# The CLI --json path relies on asdict + json.dumps(default=str).
report = identify(tmp_png_with_ai_metadata, check_visible=False)
dumped = json.dumps(asdict(report), default=str)
assert "is_ai_generated" in dumped
class TestIdentifyExifGenerator:
"""An AI generator tag in EXIF/XMP (incl. AVIF) drives attribution."""
def test_avif_firefly_software_attributed(self, tmp_path: Path):
import piexif
from PIL import Image
exif = piexif.dump({"0th": {piexif.ImageIFD.Software: b"Adobe Firefly"}, "Exif": {}, "GPS": {}, "1st": {}})
path = tmp_path / "firefly.avif"
Image.new("RGB", (64, 64), (90, 80, 70)).save(path, exif=exif)
r = identify(path, check_visible=False)
assert r.is_ai_generated is True
assert r.platform is not None
assert "Firefly" in r.platform
assert any("generator tag" in w for w in r.watermarks)
# ── Open invisible watermark (SD/SDXL/FLUX) integration ─────────────
from remove_ai_watermarks.invisible_watermark import is_available as _wm_available # noqa: E402
@pytest.mark.skipif(not _wm_available(), reason="invisible-watermark not installed")
class TestIdentifyInvisibleWatermark:
def _sdxl_watermarked(self, tmp_path: Path) -> Path:
import cv2
import numpy as np
from imwatermark import WatermarkEncoder
from remove_ai_watermarks.invisible_watermark import _BITS_48
bits = [int(b) for b in format(_BITS_48["Stable Diffusion XL"], "048b")]
enc = WatermarkEncoder()
enc.set_watermark("bits", bits)
img = np.random.default_rng(0).integers(0, 255, (512, 512, 3), dtype=np.uint8)
path = tmp_path / "sdxl.png"
cv2.imwrite(str(path), enc.encode(img, "dwtDct"))
return path
def test_sdxl_watermark_identified(self, tmp_path: Path):
r = identify(self._sdxl_watermarked(tmp_path), check_visible=False)
assert r.is_ai_generated is True
assert r.confidence == "high"
assert r.platform is not None
assert "Stable Diffusion XL" in r.platform
assert any("invisible watermark" in w.lower() for w in r.watermarks)
def test_check_invisible_false_skips(self, tmp_path: Path):
r = identify(self._sdxl_watermarked(tmp_path), check_visible=False, check_invisible=False)
assert not any(s.name == "invisible_watermark" for s in r.signals)