Python unit test with mocking assert_called for function outside class-CodePudding

I am trying to test whether a function defined outside of a class is called by a class method.

def function_a(input):
    return input

class MyClass:

    def __init__(self, user_function=function_a):
        self.user_function = user_function

    def function_b(input):
        return self.user_function(input)

I am trying to test the function call like this:

from unittest import TestCase
from unittest.mock import Mock

class TestMyClass(TestCase):
    def test_function_call(self):
        my_class = MyClass(user_function=function_a)
        mock = Mock()
        my_class.function_b(input)
        mock.function_a.assert_called()

This gives me

AssertionError: Expected 'function_a' to have been called.

I am using Python 3.6. Looking at the output I can see that function_a was called. What am I doing wrong?

CodePudding user response：

This here did the trick:

from unittest import TestCase
from unittest.mock import MagicMock

class TestMyClass(TestCase):
    def test_function_call(self):
        my_class = MyClass(user_function=MagicMock())
        my_class.function_b(input)
        my_class.user_function.assert_called()