python之如何在python中对数据库连接pymysql进行单元测试

我正在尝试编写单元测试用例以通过模拟数据库来测试以下方法。如何在不实际连接到真实数据库服务器的情况下模拟数据库连接。我尝试使用示例测试用例。我不确定这是否是正确的方法。如果我错了，请纠正我。

//MySQL.py 
    class MySQL(): 
 
        retry_interval = 20000  
 
        def link(self, server,port): 
            try: 
                return pymysql.connect(server, username='name', passwd='pwd', db='demo', int(port)) 
                sys.stdout.write('Connected to database at {}:{}\n'.format(server,port)) 
            except: 
                sys.stderr.write('Retry database connection in {} ms...\n'.format(self.retry_interval)) 
                sleep(self.retry_interval/1000.0) 
                continue 
 
//test.py 
from unittest.mock import Mock, MagicMock 
from unittest.mock import patch 
import MySQL 
 
   @patch('MySQL.pymysql') 
    def testLink(self, mysql_mock): 
        mock_cursor = Mock.MagicMock() 
        mysql_mock.connect.return_value.cursor.return_value.__enter__.return_value = mock_cursor 

请您参考如下方法:

在 MySQL.pymysql 中您真正可以测试的唯一有用的东西是 connect 方法，所以您最好直接修补它:

//test.py 
from unittest.mock import Mock, MagicMock 
from unittest.mock import patch, call 
import MySQL 
 
@patch('MySQL.pymysql.connect') 
def testLink(self, connect_mock): 
    # You can configure a return value for the connection if you need to... 
    connect_mock.return_value = MagicMock(name='connection_return', return_value=...) 
 
    # You can now test that your connection is being called... 
    self.assertEqual(1, connect_mock.call_count) 
 
    # You can also check the call parameters... 
    self.assertEqual(connect_mock.call_args_list[0], call(server, username='name', passwd='pwd',...))