gistfile1.txt

# inside of 'module.py'

def init():
    if __name__ == "__main__":
        sys.exit(main())

init()


#  inside of 'test_module.py'
def test_init():
     from myapp import module
     with mock.patch.object(module, "main", return_value=42):
        with mock.patch.object(module, "__name__", "__main__"):
            with mock.patch.object(module.sys,'exit') as mock_exit:
                module.init()
                assert mock_exit.call_args[0][0] == 42