nanobot/tests/test_context_documents.py
Xubin Ren c937c07178 fix: two bugs in document extraction pipeline
Bug 1: _drain_pending did not call extract_documents on follow-up
messages arriving mid-turn. Documents attached to queued messages were
silently dropped because _build_user_content only handles images.
Fix: call extract_documents before _build_user_content in _drain_pending.

Bug 2: extract_documents read the entire file into memory (up to 50 MB)
just to check 16 bytes of magic header for MIME detection.
Fix: read only the first 16 bytes via open()+read(16) instead of
Path.read_bytes().

Added regression tests for both bugs.

Made-with: Cursor
2026-04-14 13:15:04 +00:00

114 lines
4.3 KiB
Python

"""Tests for context builder media handling.
The ContextBuilder._build_user_content method should ONLY handle images.
Document text extraction is the responsibility of the processing layer
(AgentLoop._process_message and _drain_pending).
"""
from __future__ import annotations
from pathlib import Path
from nanobot.agent.context import ContextBuilder
from nanobot.utils.document import extract_documents
def _make_builder(tmp_path: Path) -> ContextBuilder:
"""Create a minimal ContextBuilder for testing."""
return ContextBuilder(workspace=tmp_path, timezone="UTC")
def test_build_user_content_with_no_media_returns_string(tmp_path: Path) -> None:
builder = _make_builder(tmp_path)
result = builder._build_user_content("hello", None)
assert result == "hello"
def test_build_user_content_with_image_returns_list(tmp_path: Path) -> None:
"""Image files should produce base64 content blocks."""
builder = _make_builder(tmp_path)
png = tmp_path / "test.png"
png.write_bytes(b"\x89PNG\r\n\x1a\n" + b"\x00" * 100)
result = builder._build_user_content("describe this", [str(png)])
assert isinstance(result, list)
types = [b["type"] for b in result]
assert "image_url" in types
assert "text" in types
def test_build_user_content_ignores_non_image_files(tmp_path: Path) -> None:
"""Non-image files should be silently skipped — extraction is not context builder's job."""
builder = _make_builder(tmp_path)
txt = tmp_path / "notes.txt"
txt.write_text("some text", encoding="utf-8")
result = builder._build_user_content("summarize", [str(txt)])
assert result == "summarize"
def test_build_user_content_mixed_image_and_non_image(tmp_path: Path) -> None:
"""Only images should be included; non-image files are skipped."""
builder = _make_builder(tmp_path)
png = tmp_path / "chart.png"
png.write_bytes(b"\x89PNG\r\n\x1a\n" + b"\x00" * 100)
txt = tmp_path / "report.txt"
txt.write_text("report text", encoding="utf-8")
result = builder._build_user_content("analyze", [str(png), str(txt)])
assert isinstance(result, list)
assert any(b["type"] == "image_url" for b in result)
text_parts = [b.get("text", "") for b in result if b.get("type") == "text"]
assert all("report text" not in t for t in text_parts)
# ---------------------------------------------------------------------------
# Bug detection: extract_documents must be called BEFORE _build_user_content
# to prevent document media from being silently dropped.
# This simulates the _drain_pending code path.
# ---------------------------------------------------------------------------
def test_drain_pending_path_preserves_document_text(tmp_path: Path) -> None:
"""Simulates the _drain_pending path: a pending follow-up message
with a document attachment must have its text extracted before being
passed to _build_user_content. Without extract_documents, the
document is silently dropped."""
from docx import Document
doc = Document()
doc.add_paragraph("Quarterly revenue is $5M")
docx_path = tmp_path / "report.docx"
doc.save(docx_path)
content = "summarize"
media = [str(docx_path)]
# Step 1: extract_documents separates docs from images
new_content, image_only = extract_documents(content, media)
# Step 2: _build_user_content handles only images (none left here)
builder = _make_builder(tmp_path)
result = builder._build_user_content(new_content, image_only if image_only else None)
# The document text should be present in the final content
assert "Quarterly revenue" in result
assert "summarize" in result
def test_drain_pending_path_without_extract_loses_document(tmp_path: Path) -> None:
"""Demonstrates the BUG: if _drain_pending calls _build_user_content
directly without extract_documents, document content is lost."""
from docx import Document
doc = Document()
doc.add_paragraph("Secret data in document")
docx_path = tmp_path / "report.docx"
doc.save(docx_path)
builder = _make_builder(tmp_path)
# Bug path: call _build_user_content directly with document media
result = builder._build_user_content("summarize", [str(docx_path)])
# The document text is LOST — _build_user_content ignores non-images
assert result == "summarize" # only the original text, no doc content
assert "Secret data" not in result