def test_clear_end(self):
history = UndoHistory()
self._populate_history(history)
with self.assertTraitDoesNotChange(history, 'redoable'):
with self.assertTraitChanges(history, 'undoable', count=1):
with self.assertTraitDoesNotChange(self._example, 'anytrait'):
history.clear()
self.assertEqual(history.now, 0)
self.assertFalse(history.can_undo)
self.assertFalse(history.can_redo)
