Fix Windows test timeouts from SQLite locking (#2368)

Author: jlowin

tests/conftest.py

@@ -1,9 +1,12 @@
 import socket
 from collections.abc import Callable
+from pathlib import Path
 from typing import Any
 
 import pytest
 
+from fastmcp.utilities.tests import temporary_settings
+
 
 def pytest_collection_modifyitems(items):
     """Automatically mark tests in integration_tests folder with 'integration' marker."""
@@ -21,6 +24,20 @@ def import_rich_rule():
     yield
 
 
+@pytest.fixture(autouse=True)
+def isolate_settings_home(tmp_path: Path):
+    """Ensure each test uses an isolated settings.home directory.
+
+    This prevents SQLite database locking issues on Windows when multiple
+    tests share the same DiskStore directory in settings.home / "oauth-proxy".
+    """
+    test_home = tmp_path / "fastmcp-test-home"
+    test_home.mkdir(exist_ok=True)
+
+    with temporary_settings(home=test_home):
+        yield
+
+
 def get_fn_name(fn: Callable[..., Any]) -> str:
     return fn.__name__  # ty: ignore[unresolved-attribute]