Fix very high cpu usage when a console fenrir under root and an x fenrir under your user are running at the same time.

tests/unit/test_remote_instance_registry.py

@@ -1,9 +1,24 @@
 import json
+import stat
 import time
 
 from fenrirscreenreader.core import remoteInstanceRegistry
 
 
+def test_write_instance_creates_shared_sticky_registry_directory(
+    tmp_path, monkeypatch
+):
+    registry_dir = tmp_path / "instances"
+    monkeypatch.setattr(
+        remoteInstanceRegistry, "get_registry_dir", lambda: str(registry_dir)
+    )
+
+    remoteInstanceRegistry.write_instance({"pid": 456})
+
+    mode = stat.S_IMODE(registry_dir.stat().st_mode)
+    assert mode == 0o1777
+
+
 def test_write_instance_prunes_stale_registry_files(tmp_path, monkeypatch):
     monkeypatch.setattr(
         remoteInstanceRegistry, "get_registry_dir", lambda: str(tmp_path)

tests/unit/test_unix_remote_driver.py

@@ -3,6 +3,30 @@ from unittest.mock import Mock, mock_open, patch
 from fenrirscreenreader.remoteDriver import unixDriver
 
 
+def test_watchdog_keeps_serving_when_instance_registration_fails(
+    mock_environment,
+):
+    driver = unixDriver.driver()
+    driver.env = mock_environment
+    driver.fenrirSocks = [Mock()]
+    active = Mock(value=True)
+    event_queue = Mock()
+
+    def stop_after_select(*_args):
+        active.value = False
+        return ([], [], [])
+
+    with patch.object(driver, "_get_socket_candidates", return_value=[]), patch.object(
+        driver, "_register_instance", side_effect=PermissionError("denied")
+    ), patch(
+        "fenrirscreenreader.remoteDriver.unixDriver.select.select",
+        side_effect=stop_after_select,
+    ) as select_call:
+        driver.watch_dog(active, event_queue)
+
+    select_call.assert_called_once()
+
+
 class FakeClientSocket:
     def __init__(self, data):
         self.data = data