Fix tests for Windows

tests/test_squeues_request.py

@@ -4,6 +4,7 @@ Queues that handle requests
 
 from __future__ import annotations
 
+import gc
 from abc import ABC, abstractmethod
 from typing import TYPE_CHECKING, Any
 
@@ -242,8 +243,11 @@ def test_sqlite_queue_survives_unclean_shutdown(
     key = str(tmp_path / "queue")
     queue = queue_cls.from_crawler(crawler=crawler, key=key)
     queue.push(Request("https://toscrape.com"))
-    # No close(), as if the process had been killed.
+    # No close(), as if the process had been killed. The SQLite connection is
+    # part of a reference cycle, so a garbage collection is needed to release
+    # the underlying file, which on Windows cannot be removed while open.
     del queue
+    gc.collect()
 
     queue = queue_cls.from_crawler(crawler=crawler, key=key)
     try: