todo2 = Todo.by_date(self.db_conn, '2024-01-01')[1]
self.assertEqual(todo1.children, [todo2])
self.assertEqual(todo1.parents, [])
self.assertEqual(todo2.children, [])
self.assertEqual(todo2.parents, [todo1])
# test todo1 cannot be set done with todo2 not done yet
todo2 = Todo.by_date(self.db_conn, '2024-01-01')[1]
self.assertEqual(todo1.children, [todo2])
self.assertEqual(todo1.parents, [])
self.assertEqual(todo2.children, [])
self.assertEqual(todo2.parents, [todo1])
# test todo1 cannot be set done with todo2 not done yet