Can multiple object attributes be patched at the same time? - python-3.x

Question

I am looking to reduce nesting in my tests, I was looking at with patch.multiple() for the likes of below, but can't figure out a way to get it to work.
Where mock_task_instance, mock_dag_run and success_mock_task_instance are defined in the test function.
So I was wondering if there is a way that multiple object attributes be patched at the same time?
with patch.object(
mock_task_instance, "xcom_pull", side_effect=[self.file_name, self.config]
):
with patch.object(
mock_dag_run, "get_task_instances", return_value=[success_mock_task_instance]
):
with patch.object(
success_mock_task_instance, "current_state", return_value=State.SUCCESS
):
_my_func()

Answer 1

If you are looking for a way to cleanup nested with blocks, I recommend checking out contextlib.ExitStack() as this can help with than.
Here is the example from the docs:
with ExitStack() as stack:
files = [stack.enter_context(open(fname)) for fname in filenames]
# All opened files will automatically be closed at the end of
# the with statement, even if attempts to open files later
# in the list raise an exception
See: https://docs.python.org/3/library/contextlib.html#contextlib.ExitStack
For your code, I think that might look a bit like:
with contextlib.ExitStack() as stack:
stack.enter_context(patch.object(mock_task_instance, "xcom_pull", side_effect=[self.file_name, self.config]))
stack.enter_context(patch.object(mock_dag_run, "get_task_instances", return_value=[success_mock_task_instance]))
stack.enter_context(patch.object(success_mock_task_instance, "current_state", return_value=State.SUCCESS))
_my_func()