Htykuut

@patch does not seem to produce the same behavior under 2.7 and 3.6.

Here is my project structure:

project/

    foo.py

    bar.py

    lol.py

tests/

    test_project.py

foo.py:

class Foo:

    pass

bar.py (imports Foo):

from project.foo import Foo



class Bar:

    def __init__(self):

        f = Foo()

lol.py (imports Bar):

from bar import Bar



class Lol:

    def __init__(self):

        b = Bar()

Since bar.py imports Foo using from project.foo import Foo, I am patching bar.Foo (according to where to patch docs):

test_bar.py:

from project import lol

from project import bar



@patch('bar.Foo')  # Works in 3.6, fails with 2.7

def test_lol(mock_Foo):

    l = lol.Lol()

    mock_Foo.assert_called()

This setup runs correctly in Python 3.6 but fails in 2.7 (Foo does not get patched).

However, if I switch my setup to:

test_bar.py:

from project import lol

# from project import bar # No need to import bar anymore



@patch('project.bar.Foo')  # Works in 2.7, fails with 3.6

def test_lol(mock_Foo):

    l = lol.Lol()

    mock_Foo.assert_called()

It works in 2.7 but fails in 3.6.

What is a recommended way to use @patch to make it produce results consistent between python versions?

Note: This problem only appears when I test lol.py. If I call bar.py from the unit test, I get consistent results using second setup @patch('cookie_test.bar.Foo') and it works in both 2.7 and 3.6.

I cannot replicate the difference using 2.7 vs 3.6 upon adding __init__.py files to your project directory, and changing the import of Bar in lol.py:

from project.bar import Bar

In either case, you should not need to import bar in your test - mock is taking care of finding bar by parsing the string passed to the mock decorator.

I suspect the error you're seeing is due to the fact that Python 3 uses absolute imports (https://www.python.org/dev/peps/pep-0328/)