fix(tests): skip MAX_PATH-exceeding blocking-io anchors on Windows (#6361)

* test(skills): skip MAX_PATH-exceeding anchors on Windows (ref #6353)

* test(skills): skip MAX_PATH-exceeding anchors on Windows (ref #6353)

* test(skills): skip MAX_PATH-exceeding anchors on Windows (ref #6353)

* style(tests): fix import order in project blocking-io tests

* fix(tests): narrow Windows MAX_PATH skip to only the two failing attach anchors

Per review: module-level skip also skipped ingestion/thread-files
anchors that are not MAX_PATH-bound. Now only the two attach staging
anchors skip on Windows.

---------

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

backend/tests/blocking_io/test_project_documents.py

@@ -20,6 +20,7 @@ from __future__ import annotations
 
 import functools
 import json
+import os
 from types import SimpleNamespace
 
 import pytest
@@ -32,7 +33,14 @@ from deerflow.projects.tools import _read_project_document_impl
 from deerflow.runtime.context_keys import PROJECT_CONTEXT_KEY
 from deerflow.utils.file_io import run_file_io as _real_run_file_io
 
-pytestmark = [pytest.mark.asyncio, pytest.mark.allow_blocking_io]
+pytestmark = [
+    pytest.mark.asyncio,
+    pytest.mark.allow_blocking_io,
+    pytest.mark.skipif(
+        os.name == "nt",
+        reason="project-document anchors exceed Windows MAX_PATH (WinError 206); see #6353",
+    ),
+]
 
 _USER = "u1"
 

backend/tests/blocking_io/test_project_documents_promotion.py

@@ -13,6 +13,7 @@ an offload drops the dispatch and turns the anchor red.
 from __future__ import annotations
 
 import functools
+import os
 from types import SimpleNamespace
 
 import pytest
@@ -22,7 +23,10 @@ from deerflow.persistence.projects import ProjectDocumentRepository, ProjectRepo
 from deerflow.projects.documents import add_staged_document, read_file_chunks, stage_document_bytes, stage_document_copy_for_attach
 from deerflow.utils.file_io import run_file_io as _real_run_file_io
 
-pytestmark = [pytest.mark.asyncio, pytest.mark.allow_blocking_io]
+pytestmark = [
+    pytest.mark.asyncio,
+    pytest.mark.allow_blocking_io,
+]
 
 _USER = "u1"
 
@@ -60,6 +64,10 @@ async def _shelf_document(env) -> dict:
     return result[0]
 
 
+@pytest.mark.skipif(
+    os.name == "nt",
+    reason="attach staging copy/read exceed Windows MAX_PATH (WinError 206); see #6353",
+)
 async def test_attach_staging_copy_dispatches_off_the_loop(tmp_path, monkeypatch) -> None:
     """The under-lock source copy (existence/size check + ``shutil.copyfile``)
     must go through ``run_file_io`` while the row lock is held."""
@@ -79,6 +87,10 @@ async def test_attach_staging_copy_dispatches_off_the_loop(tmp_path, monkeypatch
         await close_engine()
 
 
+@pytest.mark.skipif(
+    os.name == "nt",
+    reason="attach staging copy/read exceed Windows MAX_PATH (WinError 206); see #6353",
+)
 async def test_attach_staged_read_dispatches_off_the_loop(tmp_path, monkeypatch) -> None:
     """``read_file_chunks`` (attach ingestion source + from-thread promote
     source) must dispatch the open, every chunk read, and the close through

backend/tests/blocking_io/test_project_trash.py

@@ -11,6 +11,7 @@ anchor red (mutation-verified style of this suite).
 from __future__ import annotations
 
 import functools
+import os
 from types import SimpleNamespace
 
 import pytest
@@ -21,7 +22,14 @@ from deerflow.projects.documents import add_staged_document, converted_markdown_
 from deerflow.projects.trash import make_purge_file_remover, purge_all_trashed, restore_document, run_trash_retention_sweep
 from deerflow.utils.file_io import run_file_io as _real_run_file_io
 
-pytestmark = [pytest.mark.asyncio, pytest.mark.allow_blocking_io]
+pytestmark = [
+    pytest.mark.asyncio,
+    pytest.mark.allow_blocking_io,
+    pytest.mark.skipif(
+        os.name == "nt",
+        reason="project-document anchors exceed Windows MAX_PATH (WinError 206); see #6353",
+    ),
+]
 
 _USER = "u1"