I want to write a unit test to a function which instantiates twice a dataclass followed by calling its method. However, the actual calls of the instantiation includes the calling of the method. This is confusing to me.

Here is my code.

person.py

from dataclasses import dataclass


@dataclass
class Person:
    name: str

    def work(self):
        print(f"{self.name} is working")


def run_person():
    # It instantiates Person twice.
    for n in ["John", "Jack"]:
        person = Person(name=n)  # Instantiate a person
        person.work()  # Calling its method .work()

test_person.py

import unittest
from unittest.mock import MagicMock, call, patch

from person import run_person


class TestMain(unittest.TestCase):

    @patch("person.Person")  # Patch the Person dataclass
    def test_run_person(self, mock_person):

        mock_person.return_value = MagicMock()
        
        # This is my expectation. It should call Person() twice.
        # But the actual calls is 
        # [call(name='John'), call().work(), call(name='Jack'), call().work()]
        expected_calls = [call(name="John"), call(name="Jack")]

        run_person()

        mock_person.assert_has_calls(expected_calls)


if __name__ == "__main__":
    unittest.main()

The test gives an error

Expected: [call(name='John'), call(name='Jack')]
  Actual: [call(name='John'), call().work(), call(name='Jack'), call().work()]

Can you please explain why I receive the error message above. Shouldn’t the call of Person() and the call of Person.work() be separated? And can you please show me how to write this test properly?

Thanks