How do I set up pytest-mock for my testing environment?

How do I set up pytest-mock for my testing environment?

To set up pytest-mock, first install it using pip: pip install pytest-mock. Then, you can use the mocker fixture in your tests.

Can you give me an example of how to use the mocker fixture?

Sure! Here's a simple example:

def test_function(mocker):
    mock = mocker.patch('module.function')
    mock.return_value = 'mocked value'
    assert function() == 'mocked value'

What if I want to mock a class instead of a function?

You can mock a class in a similar way. Just patch the class and create an instance of the mock:

from module import MyClass

def test_my_class(mocker):
    mock_class = mocker.patch('module.MyClass')
    instance = mock_class.return_value
    instance.method.return_value = 'mocked method'
    assert instance.method() == 'mocked method'