Why python mock patch doesn't work?

Question

I have two files

spike.py

class T1(object):     def foo(self, afd):         return "foo"      def get_foo(self):         return self.foo(1)   def bar():     return "bar" 

test_spike.py:

from unittest import TestCase import unittest from mock import patch, MagicMock from spike import T1, bar   class TestStuff(TestCase):     @patch('spike.T1.foo', MagicMock(return_value='patched'))     def test_foo(self):         foo = T1().get_foo()         self.assertEqual('patched', foo)      @patch('spike.bar')     def test_bar(self, mock_obj):         mock_obj.return_value = 'patched'         bar = bar()         self.assertEqual('patched', bar)   if __name__ == "__main__":     unittest.main() 

When I run python test_spike.py, the first test case would pass, but the second would fail. and I switch to use nosetests test_spike.py, then both two are failed.

I don't understand how this happened? These cases supposed to pass all.

Answer 1

Access bar using spike.bar. Imported bar is not affected by mock.patch.

from unittest import TestCase import unittest from mock import patch, MagicMock from spike import T1 import spike # <----   class TestShit(TestCase):     @patch('spike.T1.foo', MagicMock(return_value='patched'))     def test_foo(self):         foo = T1().get_foo()         self.assertEqual('patched', foo)      @patch('spike.bar')     def test_bar(self, mock_obj):         mock_obj.return_value = 'patched'         bar = spike.bar() # <-----         self.assertEqual('patched', bar)   if __name__ == "__main__":     unittest.main()