fix: mock QTimer, improve timeout message

tests/conftest.py

@@ -0,0 +1,46 @@
+import pytest
+import qtpy.QtCore
+from pytestqt.exceptions import TimeoutError as QtBotTimeoutError
+from qtpy.QtCore import QTimer
+
+
+class TestableQTimer(QTimer):
+    _instances: list[tuple[QTimer, str]] = []
+    _current_test_name: str = ""
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        TestableQTimer._instances.append((self, TestableQTimer._current_test_name))
+
+    @classmethod
+    def check_all_stopped(cls, qtbot):
+        def _is_done_or_deleted(t: QTimer):
+            try:
+                return not t.isActive()
+            except RuntimeError as e:
+                return "already deleted" in e.args[0]
+
+        try:
+            qtbot.waitUntil(lambda: all(_is_done_or_deleted(timer) for timer, _ in cls._instances))
+        except QtBotTimeoutError as exc:
+            active_timers = list(filter(lambda t: t[0].isActive(), cls._instances))
+            (t.stop() for t, _ in cls._instances)
+            raise TimeoutError(f"Failed to stop all timers: {active_timers}") from exc
+        cls._instances = []
+
+
+# To support 'from qtpy.QtCore import QTimer' syntax we just replace this completely for the test session
+# see: https://docs.python.org/3/library/unittest.mock.html#where-to-patch
+qtpy.QtCore.QTimer = TestableQTimer
+
+
+@pytest.fixture(autouse=True)
+def _capture_test_name_in_qtimer(request):
+    TestableQTimer._current_test_name = request.node.name
+    yield
+    TestableQTimer._current_test_name = ""
+
+
+@pytest.fixture
+def testable_qtimer_class():
+    return TestableQTimer