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gh-christianlouis-docuelevate/tests/test_similarity.py
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"""Tests for document similarity detection.
Tests the similarity utility functions and the API endpoint
``GET /api/files/{file_id}/similar``.
"""
import json
from unittest.mock import patch
import pytest
from fastapi.testclient import TestClient
from app.models import FileRecord
from app.utils.similarity import cosine_similarity, find_similar_documents
# ---------------------------------------------------------------------------
# Unit tests for cosine_similarity
# ---------------------------------------------------------------------------
class TestCosineSimilarity:
"""Unit tests for the cosine_similarity function."""
@pytest.mark.unit
def test_identical_vectors_return_one(self):
"""Identical vectors should have similarity of 1.0."""
vec = [1.0, 2.0, 3.0]
assert cosine_similarity(vec, vec) == pytest.approx(1.0)
@pytest.mark.unit
def test_orthogonal_vectors_return_zero(self):
"""Orthogonal vectors should have similarity of 0.0."""
a = [1.0, 0.0]
b = [0.0, 1.0]
assert cosine_similarity(a, b) == pytest.approx(0.0)
@pytest.mark.unit
def test_opposite_vectors_clamped_to_zero(self):
"""Opposite vectors would give negative cosine; clamp to 0."""
a = [1.0, 0.0]
b = [-1.0, 0.0]
assert cosine_similarity(a, b) == 0.0
@pytest.mark.unit
def test_different_length_vectors_return_zero(self):
"""Vectors of different lengths should return 0.0."""
a = [1.0, 2.0, 3.0]
b = [1.0, 2.0]
assert cosine_similarity(a, b) == 0.0
@pytest.mark.unit
def test_zero_vector_returns_zero(self):
"""Zero-magnitude vector should return 0.0."""
a = [0.0, 0.0, 0.0]
b = [1.0, 2.0, 3.0]
assert cosine_similarity(a, b) == 0.0
@pytest.mark.unit
def test_similar_vectors_high_score(self):
"""Similar (but not identical) vectors should have a high score."""
a = [1.0, 2.0, 3.0]
b = [1.1, 2.1, 3.1]
score = cosine_similarity(a, b)
assert 0.99 < score <= 1.0
@pytest.mark.unit
def test_score_between_zero_and_one(self):
"""All scores should be in [0, 1]."""
a = [1.0, 0.5, 0.0]
b = [0.0, 0.5, 1.0]
score = cosine_similarity(a, b)
assert 0.0 <= score <= 1.0
@pytest.mark.unit
def test_empty_vectors_return_zero(self):
"""Empty vectors should return 0.0."""
assert cosine_similarity([], []) == 0.0
# ---------------------------------------------------------------------------
# Unit tests for find_similar_documents
# ---------------------------------------------------------------------------
class TestFindSimilarDocuments:
"""Unit tests for the find_similar_documents function."""
@pytest.mark.unit
def test_returns_empty_for_missing_file(self, db_session):
"""Should return empty list when file ID does not exist."""
result = find_similar_documents(db_session, file_id=9999)
assert result == []
@pytest.mark.unit
def test_returns_empty_when_no_ocr_text(self, db_session):
"""Should return empty list when target file has no OCR text."""
file_record = FileRecord(
filehash="abc123",
local_filename="/tmp/test.pdf",
file_size=1024,
original_filename="test.pdf",
ocr_text=None,
)
db_session.add(file_record)
db_session.commit()
result = find_similar_documents(db_session, file_id=file_record.id)
assert result == []
@pytest.mark.unit
@patch("app.utils.similarity.generate_embedding")
def test_finds_similar_documents(self, mock_embed, db_session):
"""Should find similar documents based on embedding similarity."""
# Create a target file with OCR text
target = FileRecord(
filehash="hash1",
local_filename="/tmp/target.pdf",
file_size=1024,
original_filename="target.pdf",
ocr_text="This is an invoice from Amazon for January 2026",
)
# Create a similar file
similar = FileRecord(
filehash="hash2",
local_filename="/tmp/similar.pdf",
file_size=2048,
original_filename="similar.pdf",
ocr_text="This is an invoice from Amazon for February 2026",
document_title="Amazon Invoice Feb",
mime_type="application/pdf",
)
# Create a different file
different = FileRecord(
filehash="hash3",
local_filename="/tmp/different.pdf",
file_size=512,
original_filename="different.pdf",
ocr_text="Recipe for chocolate cake with detailed instructions",
document_title="Chocolate Cake Recipe",
mime_type="application/pdf",
)
db_session.add_all([target, similar, different])
db_session.commit()
# Mock embeddings that reflect similarity
target_embedding = [1.0, 0.0, 0.0]
similar_embedding = [0.95, 0.05, 0.0]
different_embedding = [0.0, 0.0, 1.0]
def mock_embed_side_effect(text):
if "January" in text or "invoice" in text.lower()[:30]:
return target_embedding
elif "February" in text:
return similar_embedding
else:
return different_embedding
mock_embed.side_effect = mock_embed_side_effect
result = find_similar_documents(db_session, file_id=target.id, threshold=0.3)
assert len(result) == 1
assert result[0]["file_id"] == similar.id
assert result[0]["similarity_score"] > 0.9
assert result[0]["original_filename"] == "similar.pdf"
@pytest.mark.unit
@patch("app.utils.similarity.generate_embedding")
def test_respects_threshold(self, mock_embed, db_session):
"""Should filter out documents below the threshold."""
target = FileRecord(
filehash="hash1",
local_filename="/tmp/t.pdf",
file_size=100,
original_filename="target.pdf",
ocr_text="target text",
)
candidate = FileRecord(
filehash="hash2",
local_filename="/tmp/c.pdf",
file_size=100,
original_filename="candidate.pdf",
ocr_text="different text",
)
db_session.add_all([target, candidate])
db_session.commit()
# Return nearly orthogonal vectors -> low similarity
mock_embed.side_effect = lambda text: [1.0, 0.0] if "target" in text else [0.1, 0.99]
result = find_similar_documents(db_session, file_id=target.id, threshold=0.9)
assert len(result) == 0
@pytest.mark.unit
@patch("app.utils.similarity.generate_embedding")
def test_respects_limit(self, mock_embed, db_session):
"""Should respect the limit parameter."""
target = FileRecord(
filehash="hash0",
local_filename="/tmp/t.pdf",
file_size=100,
original_filename="target.pdf",
ocr_text="target text",
)
db_session.add(target)
for i in range(5):
f = FileRecord(
filehash=f"hash{i + 1}",
local_filename=f"/tmp/c{i}.pdf",
file_size=100,
original_filename=f"candidate_{i}.pdf",
ocr_text=f"similar text {i}",
)
db_session.add(f)
db_session.commit()
mock_embed.return_value = [1.0, 0.0, 0.0]
result = find_similar_documents(db_session, file_id=target.id, limit=2, threshold=0.0)
assert len(result) <= 2
@pytest.mark.unit
def test_uses_cached_embedding(self, db_session):
"""Should use cached embeddings from the database."""
cached_embedding = [0.5, 0.5, 0.5]
target = FileRecord(
filehash="hash1",
local_filename="/tmp/t.pdf",
file_size=100,
original_filename="target.pdf",
ocr_text="some text",
embedding=json.dumps(cached_embedding),
)
candidate = FileRecord(
filehash="hash2",
local_filename="/tmp/c.pdf",
file_size=100,
original_filename="candidate.pdf",
ocr_text="some text too",
embedding=json.dumps(cached_embedding),
)
db_session.add_all([target, candidate])
db_session.commit()
# No mock needed — cached embeddings should be used
result = find_similar_documents(db_session, file_id=target.id, threshold=0.0)
assert len(result) == 1
assert result[0]["similarity_score"] == pytest.approx(1.0)
# ---------------------------------------------------------------------------
# Integration tests for the API endpoint
# ---------------------------------------------------------------------------
class TestSimilarDocumentsAPI:
"""Integration tests for GET /api/files/{file_id}/similar."""
@pytest.mark.integration
def test_file_not_found(self, client: TestClient):
"""Should return 404 for non-existent file."""
response = client.get("/api/files/9999/similar")
assert response.status_code == 404
@pytest.mark.integration
def test_no_ocr_text(self, client: TestClient, db_session):
"""Should return empty results when file has no OCR text."""
file_record = FileRecord(
filehash="abc123",
local_filename="/tmp/test.pdf",
file_size=1024,
original_filename="test.pdf",
ocr_text=None,
)
db_session.add(file_record)
db_session.commit()
response = client.get(f"/api/files/{file_record.id}/similar")
assert response.status_code == 200
data = response.json()
assert data["count"] == 0
assert data["similar_documents"] == []
assert "message" in data
@pytest.mark.integration
@patch("app.utils.similarity.generate_embedding")
def test_returns_similar_documents(self, mock_embed, client: TestClient, db_session):
"""Should return similar documents with scores."""
target = FileRecord(
filehash="hash1",
local_filename="/tmp/target.pdf",
file_size=1024,
original_filename="target.pdf",
ocr_text="Invoice from Amazon January 2026",
)
similar = FileRecord(
filehash="hash2",
local_filename="/tmp/similar.pdf",
file_size=2048,
original_filename="similar_invoice.pdf",
ocr_text="Invoice from Amazon February 2026",
document_title="Amazon Invoice",
mime_type="application/pdf",
)
db_session.add_all([target, similar])
db_session.commit()
mock_embed.return_value = [1.0, 0.0, 0.0]
response = client.get(f"/api/files/{target.id}/similar")
assert response.status_code == 200
data = response.json()
assert data["file_id"] == target.id
assert data["count"] >= 1
assert len(data["similar_documents"]) >= 1
doc = data["similar_documents"][0]
assert "file_id" in doc
assert "similarity_score" in doc
assert 0 <= doc["similarity_score"] <= 1
assert "original_filename" in doc
@pytest.mark.integration
@patch("app.utils.similarity.generate_embedding")
def test_query_parameters(self, mock_embed, client: TestClient, db_session):
"""Should respect limit and threshold query parameters."""
target = FileRecord(
filehash="hash1",
local_filename="/tmp/t.pdf",
file_size=100,
original_filename="t.pdf",
ocr_text="test",
)
db_session.add(target)
for i in range(5):
f = FileRecord(
filehash=f"h{i}",
local_filename=f"/tmp/c{i}.pdf",
file_size=100,
original_filename=f"c{i}.pdf",
ocr_text=f"text {i}",
)
db_session.add(f)
db_session.commit()
mock_embed.return_value = [1.0, 0.0]
response = client.get(f"/api/files/{target.id}/similar?limit=2&threshold=0.0")
assert response.status_code == 200
data = response.json()
assert data["count"] <= 2
@pytest.mark.integration
def test_invalid_limit(self, client: TestClient, db_session):
"""Should reject invalid limit values."""
file_record = FileRecord(
filehash="abc",
local_filename="/tmp/t.pdf",
file_size=100,
original_filename="t.pdf",
)
db_session.add(file_record)
db_session.commit()
response = client.get(f"/api/files/{file_record.id}/similar?limit=0")
assert response.status_code == 422
@pytest.mark.integration
def test_invalid_threshold(self, client: TestClient, db_session):
"""Should reject threshold values outside [0, 1]."""
file_record = FileRecord(
filehash="abc",
local_filename="/tmp/t.pdf",
file_size=100,
original_filename="t.pdf",
)
db_session.add(file_record)
db_session.commit()
response = client.get(f"/api/files/{file_record.id}/similar?threshold=1.5")
assert response.status_code == 422
@pytest.mark.integration
def test_empty_ocr_text(self, client: TestClient, db_session):
"""Should return empty results when OCR text is empty string."""
file_record = FileRecord(
filehash="abc",
local_filename="/tmp/t.pdf",
file_size=100,
original_filename="t.pdf",
ocr_text="",
)
db_session.add(file_record)
db_session.commit()
response = client.get(f"/api/files/{file_record.id}/similar")
assert response.status_code == 200
data = response.json()
assert data["count"] == 0
@pytest.mark.integration
@patch("app.utils.similarity.generate_embedding")
def test_response_structure(self, mock_embed, client: TestClient, db_session):
"""Should return proper response structure for each similar document."""
target = FileRecord(
filehash="h1",
local_filename="/tmp/t.pdf",
file_size=100,
original_filename="target.pdf",
ocr_text="Some text content here",
)
other = FileRecord(
filehash="h2",
local_filename="/tmp/o.pdf",
file_size=200,
original_filename="other.pdf",
ocr_text="Some similar text content",
document_title="Other Doc",
mime_type="application/pdf",
)
db_session.add_all([target, other])
db_session.commit()
mock_embed.return_value = [1.0, 0.0]
response = client.get(f"/api/files/{target.id}/similar")
assert response.status_code == 200
data = response.json()
assert "file_id" in data
assert "similar_documents" in data
assert "count" in data
if data["count"] > 0:
doc = data["similar_documents"][0]
assert "file_id" in doc
assert "original_filename" in doc
assert "document_title" in doc
assert "similarity_score" in doc
assert "mime_type" in doc
assert "created_at" in doc