[Pytest-commit] Issue #603: monkeypatch does not work on already-imported function (hpk42/pytest)

[Marco Chomut]

New issue 603: monkeypatch does not work on already-imported function
https://bitbucket.org/hpk42/pytest/issue/603/monkeypatch-does-not-work-on-already

Marco Chomut:

Given the following tests file:

```
#!python

from project.main import foo

def test_foo(monkeypatch):
    monkeypatch.setattr('project.bar.zoo', lambda x: 0)
    assert foo() == 0

```

And this system under test:

```
#!python

# project/main.py

from project.bar import zoo

def foo():
    return zoo('lion')

```

```
#!python

# project/bar.py

def zoo(animal):
    if animal == 'lion':
        return 7

```

Then the ``zoo`` that's already been imported in ``main.py`` remains unpatched. Moving the imports around to be local to the test function would fix the problem, unless ``main.py`` is imported by other files at any point during the test suite running. Alternatively, if ``main.py`` instead does ``import project.bar`` and calls its dependency with ``project.bar.zoo('lion')``, then the test passes again. But this is cumbersome and difficult to enforce across an entire project.