Python 如何模拟 pymysqlpool.ConnectionPool 构造函数

发布于07月11日

与How do I mock part of a python constructor just for testing?类似，但明确地try 让pymysqlpool.ConnectionPool正常工作/

class DbTests(TestCase):
    @mock.patch('pymysqlpool.ConnectionPool', autospec=True)
    @mock.patch.dict(
        os.environ,
        {
            "DATASOURCES_0_SERVERID": "server1",
            "DATASOURCES_0_HOST": "non-existent",
            "DATASOURCES_0_PORT": "3307",
            "DATASOURCES_0_DATABASE": "lj_ca1",
            "DATASOURCES_0_USERNAME": "sampleuser",
            "DATASOURCES_0_PASSWORD": "password1",
            "DATASOURCES_0_TIMEZONE": "Americas/Toronto",
        },
    )    
    def test_load(self, connection_pool_mock: mock.Mock):
        ConnectionPool(
            size=2, maxsize=3, pre_create_num=2, host=os.environ["DATASOURCES_0_HOST"]
        )

我希望代码能够简单地工作，但我得到了

Pymysql.err.OperationalError:(2003年，"无法连接到‘不存在’上的MySQL服务器([Errno 11001]getaddrinfo失败)")

推荐答案

我假设您的测试文件中包含以下导入内容:

from pymysqlpool import ConnectionPool

这在测试模块中定义了名称ConnectionPool，但是您的指令patch('pymysqlpool.ConnectionPool')用名称pymysqlpool.ConnectionPool替换了对象点，因此它对另一个名称进行操作.

测试代码中的导入必须更改为:

import pymysqlpool

因此，您的测试代码变为:

import pymysqlpool

class DbTests(TestCase):
    @mock.patch('pymysqlpool.ConnectionPool', autospec=True)
    @mock.patch.dict(
        os.environ,
        {
            "DATASOURCES_0_SERVERID": "server1",
            "DATASOURCES_0_HOST": "non-existent",
            "DATASOURCES_0_PORT": "3307",
            "DATASOURCES_0_DATABASE": "lj_ca1",
            "DATASOURCES_0_USERNAME": "sampleuser",
            "DATASOURCES_0_PASSWORD": "password1",
            "DATASOURCES_0_TIMEZONE": "Americas/Toronto",
        },
    )    
    def test_load(self, connection_pool_mock: mock.Mock):
        # Note here I have changed the called to ConnectionPool
        pymysqlpool.ConnectionPool(
            size=2, maxsize=3, pre_create_num=2, host=os.environ["DATASOURCES_0_HOST"]
        )

请注意，在test_load()代码中，我还将调用更改为ConnectionPool，添加了模块pymysqlpool的名称.

我希望这个答案足以解决你的问题.