Xveeder

import pytest
from unittest import mock

class B:
    def __init__(self, db_connection):
        self.__db_connection = db_connection

class A:
    def __init__(self, b: B):
        self.__b = b

    def do_something(self) -> None:
        pass

@pytest.fixture(scope="module")
def mock_b(mocker):
    mocker.patch('path.to.B')  # Здесь 'path.to.B' - это путь к классу B, который нужно замокать
    return B(mock.MagicMock())  # Возвращаем экземпляр класса B с мок-объектом для db_connection

from threading import Lock

class ResourceContainer:
    _instance = None
    _lock = Lock()

    def __new__(cls):
        with cls._lock:
            if cls._instance is None:
                cls._instance = super().__new__(cls)
        return cls._instance

    def __init__(self):
        self._db_connection = None
        self._message_broker_connection = None
        self._config = {}

    def get_db_connection(self):
        return self._db_connection

    def set_db_connection(self, connection):
        self._db_connection = connection

    def get_message_broker_connection(self):
        return self._message_broker_connection

    def set_message_broker_connection(self, connection):
        self._message_broker_connection = connection

    def get_config(self):
        return self._config

    def set_config(self, config):
        self._config = config

def foo():
    container = ResourceContainer()
    db_conn = container.get_db_connection()
    # use db_conn

def bar():
    container = ResourceContainer()
    config = container.get_config()
    # use config