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663"""Unit tests for PDF classification service.
Tests pre-flight classification (pypdfium2-based metadata checks) and
post-extraction enrichment (content-based signal refinement).
"""
from __future__ import annotations
from unittest.mock import MagicMock, patch
import pytest
from src.services.pdf_classifier import (
FINDING_EMPTY,
FINDING_ENCRYPTED,
FINDING_FORM_ACROFORM,
FINDING_FORM_XFA,
FINDING_LOW_TEXT_DENSITY,
FINDING_MIXED_ORIENTATION,
FINDING_OVERSIZED_PAGES,
FINDING_PRESENTATION,
FINDING_SCAN_PRODUCER,
FINDING_SCANNED,
FINDING_SPREADSHEET,
FINDING_TOO_MANY_PAGES,
ClassificationFinding,
ClassificationSeverity,
PdfClassification,
PdfDocumentType,
PdfMetadata,
_check_hard_blockers,
_check_soft_warnings,
_infer_document_type,
classify_pdf,
enrich_classification,
)
pytestmark = pytest.mark.unit
# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------
def _make_mock_pdf(
*,
page_count: int = 5,
form_type: int = 0,
version: int = 17,
producer: str = "Microsoft Word",
creator: str = "Microsoft Word",
title: str = "Test Document",
is_tagged: bool = False,
page_size: tuple[float, float] = (612.0, 792.0), # US Letter
form_fields_per_page: int = 0,
open_error: Exception | None = None,
) -> MagicMock:
"""Create a mock pypdfium2.PdfDocument."""
mock_pdf = MagicMock()
if open_error:
mock_pdf.side_effect = open_error
mock_pdf.__len__ = MagicMock(return_value=page_count)
mock_pdf.get_version.return_value = version
mock_pdf.get_formtype.return_value = form_type
mock_pdf.is_tagged.return_value = is_tagged
def get_metadata_value(key: str) -> str:
return {"Producer": producer, "Creator": creator, "Title": title}.get(key, "")
mock_pdf.get_metadata_value = MagicMock(side_effect=get_metadata_value)
# Pages with dimensions and raw handles for annotation counting
def make_page(idx: int) -> MagicMock:
page = MagicMock()
page.get_size.return_value = page_size
# raw handle used by pdfium_c.FPDFPage_GetAnnotCount
page.raw = MagicMock()
return page
mock_pdf.get_page = MagicMock(side_effect=make_page)
mock_pdf._form_fields_per_page = form_fields_per_page
return mock_pdf
def _classification_codes(classification: PdfClassification) -> set[str]:
"""Extract finding codes from a classification."""
return {f.code for f in classification.findings}
# ---------------------------------------------------------------------------
# Model tests
# ---------------------------------------------------------------------------
class TestPdfClassificationModel:
"""Tests for PdfClassification properties."""
def test_has_errors_with_error_finding(self):
c = PdfClassification(
findings=[
ClassificationFinding(
code="test", severity=ClassificationSeverity.ERROR, message="fail"
)
]
)
assert c.has_errors is True
assert c.has_warnings is False
def test_has_warnings_with_warning_finding(self):
c = PdfClassification(
findings=[
ClassificationFinding(
code="test", severity=ClassificationSeverity.WARNING, message="warn"
)
]
)
assert c.has_errors is False
assert c.has_warnings is True
def test_empty_findings(self):
c = PdfClassification()
assert c.has_errors is False
assert c.has_warnings is False
assert c.error_messages == []
assert c.warning_messages == []
def test_error_messages(self):
c = PdfClassification(
findings=[
ClassificationFinding(
code="a", severity=ClassificationSeverity.ERROR, message="error one"
),
ClassificationFinding(
code="b", severity=ClassificationSeverity.WARNING, message="warn one"
),
ClassificationFinding(
code="c", severity=ClassificationSeverity.ERROR, message="error two"
),
]
)
assert c.error_messages == ["error one", "error two"]
assert c.warning_messages == ["warn one"]
# ---------------------------------------------------------------------------
# Hard blocker tests
# ---------------------------------------------------------------------------
class TestHardBlockers:
"""Tests for _check_hard_blockers."""
def test_acroform_with_fields_detected(self):
"""AcroForm declared AND real widget fields present → block."""
c = PdfClassification(metadata=PdfMetadata(page_count=5, form_type=1, form_field_count=10))
_check_hard_blockers(c)
assert FINDING_FORM_ACROFORM in _classification_codes(c)
assert c.findings[0].severity == ClassificationSeverity.ERROR
assert "10" in c.findings[0].message
def test_acroform_without_fields_is_clean(self):
"""AcroForm declared but zero widget fields → not a real form, allow."""
c = PdfClassification(metadata=PdfMetadata(page_count=5, form_type=1, form_field_count=0))
_check_hard_blockers(c)
assert FINDING_FORM_ACROFORM not in _classification_codes(c)
def test_xfa_full_with_fields_detected(self):
"""XFA full (form_type=2) with fields → block as XFA."""
c = PdfClassification(metadata=PdfMetadata(page_count=5, form_type=2, form_field_count=50))
_check_hard_blockers(c)
assert FINDING_FORM_XFA in _classification_codes(c)
assert c.findings[0].severity == ClassificationSeverity.ERROR
def test_xfa_foreground_with_fields_detected(self):
"""XFA foreground/hybrid (form_type=3) with fields → block as XFA."""
c = PdfClassification(metadata=PdfMetadata(page_count=5, form_type=3, form_field_count=284))
_check_hard_blockers(c)
assert FINDING_FORM_XFA in _classification_codes(c)
assert "284" in c.findings[0].message
def test_no_form_is_clean(self):
c = PdfClassification(metadata=PdfMetadata(page_count=5, form_type=0))
_check_hard_blockers(c)
assert len(c.findings) == 0
def test_empty_pdf(self):
c = PdfClassification(metadata=PdfMetadata(page_count=0))
_check_hard_blockers(c)
assert FINDING_EMPTY in _classification_codes(c)
@patch("src.services.pdf_classifier.settings")
def test_too_many_pages(self, mock_settings):
mock_settings.pdf_max_pages = 50
c = PdfClassification(metadata=PdfMetadata(page_count=51))
_check_hard_blockers(c)
assert FINDING_TOO_MANY_PAGES in _classification_codes(c)
assert "51" in c.findings[0].message
assert "50" in c.findings[0].message
@patch("src.services.pdf_classifier.settings")
def test_exactly_max_pages_is_ok(self, mock_settings):
mock_settings.pdf_max_pages = 50
c = PdfClassification(metadata=PdfMetadata(page_count=50))
_check_hard_blockers(c)
assert FINDING_TOO_MANY_PAGES not in _classification_codes(c)
# ---------------------------------------------------------------------------
# Soft warning tests
# ---------------------------------------------------------------------------
class TestSoftWarnings:
"""Tests for _check_soft_warnings."""
def test_scanner_producer_detected(self):
c = PdfClassification(
metadata=PdfMetadata(page_count=5, producer="Adobe Scan 21.09")
)
_check_soft_warnings(c)
assert FINDING_SCAN_PRODUCER in _classification_codes(c)
assert c.findings[0].severity == ClassificationSeverity.WARNING
def test_scanner_creator_detected(self):
c = PdfClassification(
metadata=PdfMetadata(page_count=5, creator="CamScanner Pro")
)
_check_soft_warnings(c)
assert FINDING_SCAN_PRODUCER in _classification_codes(c)
def test_normal_producer_no_warning(self):
c = PdfClassification(
metadata=PdfMetadata(page_count=5, producer="Microsoft Word 2021")
)
_check_soft_warnings(c)
assert FINDING_SCAN_PRODUCER not in _classification_codes(c)
def test_oversized_pages(self):
# A0 is 2384 x 3370; make page much bigger
c = PdfClassification(
metadata=PdfMetadata(
page_count=2,
page_dimensions=[(612.0, 792.0), (5000.0, 5000.0)],
)
)
_check_soft_warnings(c)
assert FINDING_OVERSIZED_PAGES in _classification_codes(c)
assert c.findings[0].details["oversized_pages"] == [2]
def test_normal_pages_no_oversized_warning(self):
c = PdfClassification(
metadata=PdfMetadata(
page_count=2,
page_dimensions=[(612.0, 792.0), (612.0, 792.0)],
)
)
_check_soft_warnings(c)
assert FINDING_OVERSIZED_PAGES not in _classification_codes(c)
def test_mixed_orientation(self):
c = PdfClassification(
metadata=PdfMetadata(
page_count=3,
page_dimensions=[
(612.0, 792.0), # portrait
(792.0, 612.0), # landscape
(612.0, 792.0), # portrait
],
)
)
_check_soft_warnings(c)
assert FINDING_MIXED_ORIENTATION in _classification_codes(c)
def test_uniform_orientation_no_warning(self):
c = PdfClassification(
metadata=PdfMetadata(
page_count=2,
page_dimensions=[(612.0, 792.0), (612.0, 792.0)],
)
)
_check_soft_warnings(c)
assert FINDING_MIXED_ORIENTATION not in _classification_codes(c)
def test_single_page_no_mixed_orientation(self):
c = PdfClassification(
metadata=PdfMetadata(
page_count=1,
page_dimensions=[(612.0, 792.0)],
)
)
_check_soft_warnings(c)
assert FINDING_MIXED_ORIENTATION not in _classification_codes(c)
def test_presentation_producer(self):
c = PdfClassification(
metadata=PdfMetadata(page_count=10, producer="Microsoft PowerPoint 2019")
)
_check_soft_warnings(c)
assert FINDING_PRESENTATION in _classification_codes(c)
def test_keynote_producer(self):
c = PdfClassification(
metadata=PdfMetadata(page_count=10, creator="Keynote 12.0")
)
_check_soft_warnings(c)
assert FINDING_PRESENTATION in _classification_codes(c)
def test_spreadsheet_producer(self):
c = PdfClassification(
metadata=PdfMetadata(page_count=3, producer="Microsoft Excel 2021")
)
_check_soft_warnings(c)
assert FINDING_SPREADSHEET in _classification_codes(c)
# ---------------------------------------------------------------------------
# Document type inference tests
# ---------------------------------------------------------------------------
class TestInferDocumentType:
"""Tests for _infer_document_type."""
def test_form_type(self):
c = PdfClassification(
findings=[
ClassificationFinding(
code=FINDING_FORM_ACROFORM,
severity=ClassificationSeverity.ERROR,
message="form",
)
]
)
_infer_document_type(c)
assert c.document_type == PdfDocumentType.FORM
def test_scanned_type(self):
c = PdfClassification(
findings=[
ClassificationFinding(
code=FINDING_SCANNED,
severity=ClassificationSeverity.WARNING,
message="scanned",
)
]
)
_infer_document_type(c)
assert c.document_type == PdfDocumentType.SCANNED
def test_scan_producer_type(self):
c = PdfClassification(
findings=[
ClassificationFinding(
code=FINDING_SCAN_PRODUCER,
severity=ClassificationSeverity.WARNING,
message="scan producer",
)
]
)
_infer_document_type(c)
assert c.document_type == PdfDocumentType.SCANNED
def test_presentation_type(self):
c = PdfClassification(
findings=[
ClassificationFinding(
code=FINDING_PRESENTATION,
severity=ClassificationSeverity.WARNING,
message="slides",
)
]
)
_infer_document_type(c)
assert c.document_type == PdfDocumentType.PRESENTATION
def test_spreadsheet_type(self):
c = PdfClassification(
findings=[
ClassificationFinding(
code=FINDING_SPREADSHEET,
severity=ClassificationSeverity.WARNING,
message="sheet",
)
]
)
_infer_document_type(c)
assert c.document_type == PdfDocumentType.SPREADSHEET
def test_standard_no_findings(self):
c = PdfClassification()
_infer_document_type(c)
assert c.document_type == PdfDocumentType.STANDARD
def test_form_takes_precedence_over_scanned(self):
c = PdfClassification(
findings=[
ClassificationFinding(
code=FINDING_FORM_ACROFORM,
severity=ClassificationSeverity.ERROR,
message="form",
),
ClassificationFinding(
code=FINDING_SCANNED,
severity=ClassificationSeverity.WARNING,
message="scanned",
),
]
)
_infer_document_type(c)
assert c.document_type == PdfDocumentType.FORM
# ---------------------------------------------------------------------------
# classify_pdf integration tests (with mocked pypdfium2)
# ---------------------------------------------------------------------------
class TestClassifyPdf:
"""Tests for classify_pdf with mocked pypdfium2.PdfDocument.
Note: The low-level pdfium_c annotation counting cannot be mocked
through mock PdfDocument pages (they don't have real PDFium handles).
Form detection tests that need specific form_field_count values are
covered by TestHardBlockers above. These integration tests verify
the full classify_pdf flow for non-form scenarios and use
_extract_metadata + _check_hard_blockers patching for form cases.
"""
@patch("pypdfium2.PdfDocument")
def test_standard_pdf(self, mock_pdf_cls):
mock_pdf_cls.return_value = _make_mock_pdf()
result = classify_pdf(b"fake-pdf-bytes")
assert result.document_type == PdfDocumentType.STANDARD
assert not result.has_errors
assert result.metadata.page_count == 5
assert result.elapsed_ms >= 0
@patch("pypdfium2.PdfDocument")
def test_encrypted_pdf(self, mock_pdf_cls):
mock_pdf_cls.side_effect = Exception("password required")
result = classify_pdf(b"fake-pdf-bytes")
assert result.has_errors
assert FINDING_ENCRYPTED in _classification_codes(result)
assert result.metadata.is_encrypted
@patch("src.services.pdf_classifier._extract_metadata")
@patch("pypdfium2.PdfDocument")
def test_form_pdf_with_fields_blocked(self, mock_pdf_cls, mock_extract):
"""AcroForm with actual widget fields → blocked."""
mock_pdf_cls.return_value = _make_mock_pdf(form_type=1)
def populate_metadata(pdf, classification):
classification.metadata.page_count = 5
classification.metadata.form_type = 1
classification.metadata.form_field_count = 50
mock_extract.side_effect = populate_metadata
result = classify_pdf(b"fake-pdf-bytes")
assert result.has_errors
assert result.document_type == PdfDocumentType.FORM
assert FINDING_FORM_ACROFORM in _classification_codes(result)
@patch("pypdfium2.PdfDocument")
def test_form_type_without_fields_allowed(self, mock_pdf_cls):
"""AcroForm declared but no real widget fields → not blocked."""
mock_pdf_cls.return_value = _make_mock_pdf(form_type=1)
result = classify_pdf(b"fake-pdf-bytes")
# form_field_count stays 0 because mock pages have no real annotations
assert not result.has_errors
assert FINDING_FORM_ACROFORM not in _classification_codes(result)
@patch("src.services.pdf_classifier._extract_metadata")
@patch("pypdfium2.PdfDocument")
def test_xfa_form_blocked(self, mock_pdf_cls, mock_extract):
mock_pdf_cls.return_value = _make_mock_pdf(form_type=2)
def populate_metadata(pdf, classification):
classification.metadata.page_count = 5
classification.metadata.form_type = 2
classification.metadata.form_field_count = 50
mock_extract.side_effect = populate_metadata
result = classify_pdf(b"fake-pdf-bytes")
assert result.has_errors
assert FINDING_FORM_XFA in _classification_codes(result)
@patch("src.services.pdf_classifier._extract_metadata")
@patch("pypdfium2.PdfDocument")
def test_xfa_foreground_blocked(self, mock_pdf_cls, mock_extract):
"""form_type=3 (XFA foreground/hybrid) with fields → blocked as XFA."""
mock_pdf_cls.return_value = _make_mock_pdf(form_type=3)
def populate_metadata(pdf, classification):
classification.metadata.page_count = 11
classification.metadata.form_type = 3
classification.metadata.form_field_count = 284
mock_extract.side_effect = populate_metadata
result = classify_pdf(b"fake-pdf-bytes")
assert result.has_errors
assert FINDING_FORM_XFA in _classification_codes(result)
@patch("pypdfium2.PdfDocument")
def test_too_many_pages_blocked(self, mock_pdf_cls):
mock_pdf_cls.return_value = _make_mock_pdf(page_count=60)
result = classify_pdf(b"fake-pdf-bytes")
assert result.has_errors
assert FINDING_TOO_MANY_PAGES in _classification_codes(result)
@patch("pypdfium2.PdfDocument")
def test_scanner_producer_warns(self, mock_pdf_cls):
mock_pdf_cls.return_value = _make_mock_pdf(producer="Adobe Scan 21.09.24")
result = classify_pdf(b"fake-pdf-bytes")
assert not result.has_errors
assert result.has_warnings
assert FINDING_SCAN_PRODUCER in _classification_codes(result)
assert result.document_type == PdfDocumentType.SCANNED
@patch("pypdfium2.PdfDocument")
def test_metadata_extraction(self, mock_pdf_cls):
mock_pdf_cls.return_value = _make_mock_pdf(
page_count=10,
version=20,
producer="LaTeX",
creator="pdfTeX",
title="My Thesis",
is_tagged=True,
)
result = classify_pdf(b"fake-pdf-bytes")
assert result.metadata.page_count == 10
assert result.metadata.pdf_version == "2.0"
assert result.metadata.producer == "LaTeX"
assert result.metadata.creator == "pdfTeX"
assert result.metadata.title == "My Thesis"
assert result.metadata.is_tagged is True
# ---------------------------------------------------------------------------
# Post-extraction enrichment tests
# ---------------------------------------------------------------------------
class TestEnrichClassification:
"""Tests for enrich_classification."""
def test_scanned_document_detected(self):
c = PdfClassification()
enrich_classification(
c, total_pages=10, total_chars=200, figure_count=0, layout_hints={}
)
assert FINDING_SCANNED in _classification_codes(c)
assert c.document_type == PdfDocumentType.SCANNED
def test_low_text_density_detected(self):
c = PdfClassification()
enrich_classification(
c, total_pages=10, total_chars=1500, figure_count=0, layout_hints={}
)
assert FINDING_LOW_TEXT_DENSITY in _classification_codes(c)
def test_normal_density_no_warning(self):
c = PdfClassification()
enrich_classification(
c, total_pages=10, total_chars=5000, figure_count=0, layout_hints={}
)
assert FINDING_SCANNED not in _classification_codes(c)
assert FINDING_LOW_TEXT_DENSITY not in _classification_codes(c)
def test_zero_pages_skipped(self):
c = PdfClassification()
enrich_classification(
c, total_pages=0, total_chars=0, figure_count=0, layout_hints={}
)
assert len(c.findings) == 0
def test_presentation_from_layout_hints(self):
c = PdfClassification()
layout_hints = {str(i): "presentation" for i in range(1, 11)}
enrich_classification(
c, total_pages=10, total_chars=5000, figure_count=5, layout_hints=layout_hints
)
assert FINDING_PRESENTATION in _classification_codes(c)
assert c.document_type == PdfDocumentType.PRESENTATION
def test_presentation_threshold_not_met(self):
c = PdfClassification()
layout_hints = {
"1": "presentation",
"2": "single_column",
"3": "single_column",
"4": "single_column",
"5": "single_column",
}
enrich_classification(
c, total_pages=5, total_chars=5000, figure_count=0, layout_hints=layout_hints
)
assert FINDING_PRESENTATION not in _classification_codes(c)
def test_no_duplicate_scanned_finding(self):
"""If pre-flight already found scanned, don't add again."""
c = PdfClassification(
findings=[
ClassificationFinding(
code=FINDING_SCANNED,
severity=ClassificationSeverity.WARNING,
message="already found",
)
]
)
enrich_classification(
c, total_pages=10, total_chars=200, figure_count=0, layout_hints={}
)
scanned_findings = [f for f in c.findings if f.code == FINDING_SCANNED]
assert len(scanned_findings) == 1
def test_no_duplicate_presentation_finding(self):
"""If pre-flight found presentation producer, don't add layout-based one."""
c = PdfClassification(
findings=[
ClassificationFinding(
code=FINDING_PRESENTATION,
severity=ClassificationSeverity.WARNING,
message="already found",
)
]
)
layout_hints = {str(i): "presentation" for i in range(1, 11)}
enrich_classification(
c, total_pages=10, total_chars=5000, figure_count=5, layout_hints=layout_hints
)
pres_findings = [f for f in c.findings if f.code == FINDING_PRESENTATION]
assert len(pres_findings) == 1
def test_enrichment_updates_document_type(self):
"""After enrichment, document type is re-inferred."""
c = PdfClassification(document_type=PdfDocumentType.STANDARD)
enrich_classification(
c, total_pages=10, total_chars=100, figure_count=0, layout_hints={}
)
assert c.document_type == PdfDocumentType.SCANNED