模拟自动连接的对象并从该对象调用方法

import unittest
from unittest.mock import Mock

# 假设我们有一个需要连接的远程服务类
class RemoteService:
    def connect(self):
        print("Connecting to remote service...")
        # 实际的连接逻辑

    def fetch_data(self):
        print("Fetching data from remote service...")
        # 实际的数据获取逻辑
        return "real data"

# 我们需要测试的类，它依赖于RemoteService
class DataProcessor:
    def __init__(self, remote_service):
        self.remote_service = remote_service

    def process_data(self):
        self.remote_service.connect()
        data = self.remote_service.fetch_data()
        return f"Processed {data}"

# 测试用例
class TestDataProcessor(unittest.TestCase):
    def test_process_data(self):
        # 创建一个模拟的RemoteService对象
        mock_remote_service = Mock(spec=RemoteService)
        mock_remote_service.fetch_data.return_value = "mock data"

        # 使用模拟对象创建DataProcessor实例
        processor = DataProcessor(mock_remote_service)

        # 调用process_data方法并断言结果
        result = processor.process_data()
        self.assertEqual(result, "Processed mock data")
        mock_remote_service.connect.assert_called_once()
        mock_remote_service.fetch_data.assert_called_once()

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