How to mock python module in unittest

Question

I have a problem when mocking in unittest.

#!/usr/bin/env python
import sys
sys.modules["foo.Bar"] = __import__("mock_bar")
import foo.Bar
print foo.Bar.__name__

I've got an ImportError exception in line 4. I don't know why since I have do some mock at line 3. There is a reference of how to mock import here. Here's the error message:

Traceback (most recent call last):
  File "test.py", line 4, in <module>
    import foo.Bar
ImportError: No module named foo.Bar

"import foo.Bar" should equal to "__import__('foo.Bar')", and before that I've hacked sys.modules to pretend module 'foo.Bar' has been already imported. Why python still try to import foo.Bar and complain?

@MartijnPieters Actually, "foo" is a package name and "Bar" is a module name. The "foo/Bar.py" is the target which I want to mock. So there's no "foo/Bar.py" file, but "mock_bar.py" instead. — Meng, Mar 14 '13 at 13:10
Yeah, understood that. Any reason you are using `__import__` instead of the `importlib` module, btw.? — Martijn Pieters, Mar 14 '13 at 13:13
`importlib` was added in Python 2.7 too, but that won't help you either. — Martijn Pieters, Mar 14 '13 at 13:34
What is the point of mocking an non-existing module ? That's actually not mocking. If you wan't to just have o mock at foo.Bar, then make up some objects too assing `foo.Bar = mock.Mock()` — smido, Apr 27 '22 at 08:38

score 0 · Answer 1 · answered Jul 01 '14 at 12:31

0

Try doing import foo before your __import__ line: I think it could help.

answered Jul 01 '14 at 12:31

user1735594

437
1
6
9

How to mock python module in unittest

1 Answers1