如何使用Ansible Playbook与特定群组一起玩(How to Play with particular group using Ansible Playbook)

 我几乎不做任何补丁，但我相信你要修补得太晚，或者说错了。 SMTP已经导入，导致直接引用原始类 - 它将不再在smtplib查找。 相反，您需要修补该引用。 让我们使用一个更现实的例子，其中有module.py和test_module.py 。 
 
 module.py ： 
 
import smtplib
from smtplib import SMTP # Basically a local variable

def get_smtp_unqualified():
    return SMTP # Doing a lookup in this module

def get_smtp_qualified():
    return smtplib.SMTP # Doing a lookup in smtplib
 
 test_module.py 
 
import unittest
from unittest import patch
from module import get_smtp_unqualified, get_smtp_qualified

class ModuleTest(unittest.TestCase):
    def test_get_smtp_unqualified(self):
        with patch('module.SMTP') as smtp:
            self.assertIs(smtp, get_smtp_unqualified())

    def test_get_smtp_qualified_local(self):
        with patch('module.smtplib.SMTP') as smtp:
            self.assertIs(smtp, get_smtp_qualified())

    def test_get_smtp_qualified_global(self):
        with patch('smtplib.SMTP') as smtp:
            self.assertIs(smtp, get_smtp_qualified())
 
 只要你在查找之前及时修补，它就会做你想要的 - 3次通过测试。 最早的时间是在导入除unittest之外的任何其他模块之前。 那些模块还没有导入smtplib.SMTP 。 更多关于这一点 。 但是，当您的测试分为多个模块时，它会变得棘手。 
 
 修补本质上是脏的。 你正在搞乱另一个人的内部。 为了使它工作，你必须在里面看。 如果内部发生变化，测试将会中断。 这就是为什么你应该把它作为最后的手段，并喜欢不同的手段，如依赖注入。 这是一个完全不同的主题，但无论如何，不​​要依赖修补来防止消息外出 - 也改变配置！ 

I hardly do any patching, but I believe you're patching either too late, or the wrong thing. SMTP has already been imported, resulting in a direct reference to the original class—it will not be looked up in smtplib anymore. Instead, you'd need to patch that reference. Let's use a more realistic example, in which you have module.py and test_module.py.
 
module.py:
 
import smtplib
from smtplib import SMTP # Basically a local variable

def get_smtp_unqualified():
    return SMTP # Doing a lookup in this module

def get_smtp_qualified():
    return smtplib.SMTP # Doing a lookup in smtplib
 
test_module.py
 
import unittest
from unittest import patch
from module import get_smtp_unqualified, get_smtp_qualified

class ModuleTest(unittest.TestCase):
    def test_get_smtp_unqualified(self):
        with patch('module.SMTP') as smtp:
            self.assertIs(smtp, get_smtp_unqualified())

    def test_get_smtp_qualified_local(self):
        with patch('module.smtplib.SMTP') as smtp:
            self.assertIs(smtp, get_smtp_qualified())

    def test_get_smtp_qualified_global(self):
        with patch('smtplib.SMTP') as smtp:
            self.assertIs(smtp, get_smtp_qualified())
 
As long as you patch in time before a lookup, it does what you want—3 passing tests. The very earliest time would be before importing any other modules than unittest. Then those modules will not have imported smtplib.SMTP yet. More on that here. It gets tricky though, when your tests are split over multiple modules.
 
Patching is inherently dirty. You're messing with another's internals. To make it work, you have to look on the inside. If the inside changes, tests will break. That's why you should consider it a last resort and prefer different means, such as dependency injection. That's a whole different topic, but in any case, don't rely on patching to prevent messages from going out—also change the configuration!