Python: Mocking a context manager

Question

I don\'t understand why I can\'t mock NamedTemporaryFile.name in this example:

from mock import Mock, patch
import unittest
import tempfile

def myfunc():
           


        

Answer 1

You are setting the wrong mock: mock_tmp is not the context manager, but instead returns a context manager. Replace your setup line with:

mock_tmp.return_value.__enter__.return_value.name = mytmpname

and your test will work.