Common mocks defined with @patch to several test case functions in Python

Question

I have this testing code in Python using mocks (simplified):

from unittest import TestCase
from mock import patch

class TestClass(TestCase):

    @patch("mymodule.function1")
    @patch("mymodule.function2")
    @patch("mymodule.function3")
    def test_case_1(self, function3_mock, function2_mock, function1_mock):
       # code for test_case_1
       ...

    @patch("mymodule.function1")
    @patch("mymodule.function2")
    @patch("mymodule.function3")
    def test_case_2(self, function3_mock, function2_mock, function1_mock):
       # code for test_case_2
       ...

    @patch("mymodule.function1")
    @patch("mymodule.function2")
    @patch("mymodule.function3")
    def test_case_3(self, function3_mock, function2_mock, function1_mock):
       # code for test_case_3
       ...

    ...

I wonder if there is some way of simplifying this, so:

• I don't repeat all the time the three @patch(...) statements in each test case function
• I don't need to pass the mock function to the test case function, so I can call write just def test_case_1(self) for instance

Is that possible? Could you provide some hints/advice?

Thanks in advance!

Answer 1

Refactored this way achieves both objectives:

from unittest import TestCase
from mock import patch, Mock

function1_mock = Mock()
function2_mock = Mock()
function3_mock = Mock()

@patch("mymodule.function1", function1_mock)
@patch("mymodule.function2", function2_mock)
@patch("mymodule.function3", function3_mock)
class TestClass(TestCase):

    def test_case_1(self):
       # code for test_case_1
       ...

    def test_case_2(self):
       # code for test_case_2
       ...

    def test_case_3(self):
       # code for test_case_3
       ...

    ...