I am trying to mock a function call which is inside the actual function I am trying to mock. I want to check that an algorithm is correct, but I have a draw_data() inside the function, which is recieved as a parameter. I don’t want to use that in the unittests, however. My actual program is a algorithm visualiser, so the draw_data() is supposed to display it on a gui.

Below is what I’ve tried, although it doesn’t seem to work. It should “ignore” the draw_data, as it is unneeded for the unittests. Recieved error on run: AttributeError: <module 'src.algorithms' from 'C:\Users\frowl\PycharmProjects\StructViz\src\algorithms.py'> does not have the attribute 'draw_data'

/src/tests/algorithms_test.py:

class TestCase(unittest.TestCase):
    @patch('src.algorithms.draw_data')
    def test_bubble_sort(self, draw_data_mock):

        draw_data_mock.return_value = 'mocked stuff'

        data = [9, 2, 7, 5, 5, 23, 61, 9, 9, 11]

        algorithms.bubble_sort(data, draw_data_mock, 0)

        self.assertEqual([2, 5, 5, 7, 9, 9, 9, 11, 23, 61], data)

/src/algorithms.py:

    """Bubble sort algorithm"""

    data_len = len(data)

    for i in range(data_len):
        for j in range(0, data_len - i - 1):

            if data[j] > data[j + 1]:
                data[j], data[j + 1] = data[j + 1], data[j]

                draw_data(data, ['Green' if x == j + 1 else 'Red' for x in range(len(data))])
                time.sleep(speed)

/src/app.py:

 def draw_data(self, data: list[int], color: list[str]) -> None:
        self.sort_canvas.delete('all')

        canvas_height, canvas_width = 380, 500
        x_width = canvas_width / (len(data) + 1)
        offset, spacing = 30, 10

        normalized_data = [i / max(data) for i in data]