tracking attribute accesses

from unittest import mock

class AttributeTrackMock(mock.Mock):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.attr_accesses = []

    def __getattr__(self, attr):
        res = super().__getattr__(attr)
        self.attr_accesses.append(res)
        return res