Question

I’ve got a following structure:

|-- dirBar
|   |-- __init__.py
|   |-- bar.py
|-- foo.py
`-- test.py

bar.py

def returnBar():
    return 'Bar'

foo.py

from dirBar.bar import returnBar

def printFoo():
    print returnBar()

test.py

from mock import Mock

from foo import printFoo
from dirBar import bar

bar.returnBar = Mock(return_value='Foo')

printFoo()

the result of python test.py is Bar.

How to mock the printBar to make it return Foo so that printFoo will print it?

EDIT: Without modifying any other file that test.py

Answer 1

I’m guessing you are going to mock the function returnBar, you’d like to use patch decorator:

from mock import patch

from foo import printFoo

@patch('foo.returnBar')
def test_printFoo(mockBar):
    mockBar.return_value = 'Foo'
    printFoo()

test_printFoo()