I'm trying to mock something while testing a Django app using the imaginatively named Mock testing library. I can't seem to quite get it to work, I'm trying to do this:
models.py
from somelib import FooClass
class Promotion(models.Model):
foo = models.ForeignKey(FooClass)
def bar(self):
print "Do something I don't want!"
test.py
class ViewsDoSomething(TestCase):
view = 'my_app.views.do_something'
def test_enter_promotion(self):
@patch.object(my_app.models.FooClass, 'bar')
def fake_bar(self, mock_my_method):
print "Do something I want!"
return True
self.client.get(reverse(view))
What am I doing wrong?
To add onto Kit's answer, specifying a 3rd argument to patch.object()
allows the mocked object/method to be specified. Otherwise, a default MagicMock
object is used.
def fake_bar(self):
print "Do something I want!"
return True
@patch.object(my_app.models.FooClass, 'bar', fake_bar)
def test_enter_promotion(self):
self.client.get(reverse(view))
# Do something I want!
Note that, if you specify the mocking object, then the default MagicMock()
is no longer passed into the patched object -- e.g. no longer:
def test_enter_promotion(self, mock_method):
but instead:
def test_enter_promotion(self):
https://docs.python.org/3/library/unittest.mock.html#patch-object
Ah I was confused on where to apply that patch decorator. Fixed:
class ViewsDoSomething(TestCase):
view = 'my_app.views.do_something'
@patch.object(my_app.models.FooClass, 'bar')
def test_enter_promotion(self, mock_method):
self.client.get(reverse(view))
If you'd like to do assert_called
etc. against the mocked method, use the patch.object
and wrap replacement method in a MagicMock(side_effect=)
, ie:
with patch.object(class_to_mock, attribute_name, \
MagicMock(side_effect=replacement_method)) as replacement_method_mock:
eg.:
from unittest.mock import patch, MagicMock
def fake_bar(self):
print "Do something I want!"
return True
def test_enter_promotion(self):
with patch.object(my_app.models.FooClass, 'bar', MagicMock(side_effect=fake_bar)) as fake_bar_mock:
self.client.get(reverse(view))
# Do something I want!
fake_bar_mock.assert_called()
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