在 Python unittest 中模拟和修补 keystoneclient

Question

我正在为 class 编写单元测试，如下所示。我正在尝试断言是否使用补丁 keystoneclient 正确调用了日志记录。 class 如下所示。问题是，我无法通过 for 语句并且即使在修补 CredentialManager 之后也永远无法到达 LOGGER.warning 或 LOGGER.info。我是整个单元测试和模拟的新手，所以我可能没有清楚地理解某些东西。

from keystoneclient.v3.client import Client
from keystoneclient.v3.credentials import CredentialManager
import logging

LOGGER = logging.getLogger(__name__)

class MyClass(object):

    def __init__(self):
    ...

    def myfunc(self):

        new_credentials = {}
        client = Client(
            username=self.username,
            password=self.password,
            auth_url=self.auth_url,
            user_domain_name=self.user_domain_name,
            domain_name=self.domain_name
        )

        abc = CredentialManager(client)

        for credential in abc.list():

            defg = str(credential.type)
            (access, secret) = _anotherfunc(credential.blob)

            if not defg:
                LOGGER.warning('no abc')

            if defg in new_credentials:
                LOGGER.info('Ignoring duplate')

            new_credentials[defg] = (access, secret)

我的单元测试看起来像这样，

import unittest
from mock import patch, MagicMock
import MyClass

LOGGER = logging.getLogger('my_module')

@patch('MyClass.Client', autospec = True)
@patch('MyClass.CredentialManager', autospec = True)
class TestMyClass(unittest.TestCase):

    def test_logger_warning(self,,mock_client, mock_cm):
        with patch.object(LOGGER, 'warning') as mock_warning:
            obj = MyClass()
            mock_warning.assert_called_with('no abc')

我得到的错误看起来像这样。

    for credential in abc.list():
AttributeError: 'tuple' object has no attribute 'list'

因此，即使在使用 autospect 修补 CredentialManager 之后，我仍然在 abc.list() 上遇到错误。我需要达到可以测试 LOGGER 的地步，但似乎此修补程序不适用于 list()。我应该如何让这个错误消失并能够通过 for 语句以便我可以在日志记录时断言？

Answer 1

这个答案要涵盖多少细节：

补丁顺序：@patch 装饰器作为堆栈应用，这意味着第一个装饰器 -> 最后一个模拟参数
如果你想要 CredentialManager().list() return 包含空 type 的内容，你应该使用你的 mock_cm 来完成它
如果你想测试一些东西，你应该打电话给 obj.myfunc():)

代码：

导入单元测试来自模拟导入补丁，Mock 导入 MyClass

@patch('MyClass.Client', autospec=True)
@patch('MyClass.CredentialManager', autospec=True)
class TestMyClass(unittest.TestCase):
    #Use decorator for test case too... is simpler and neat
    @patch("MyClass.LOGGER", autospec=True)
    def test_logger_warning(self, mock_logger, mock_cm, mock_client):
        #pay attention to the mock argument order (first local and the the stack of patches
        # Extract the mock that will represent you abc
        mock_abc = mock_cm.return_value
        # Build a mock for credential with desidered empty type
        mock_credential = Mock(type="")
        # Intrument list() method to return your credential
        mock_abc.list.return_value = [mock_credential]
        obj = MyClass.MyClass()
        # Call the method
        obj.myfunc()
        # Check your logger
        mock_logger.warning.assert_called_with('no abc')

对所有补丁使用 autospec=True 的好处：这是一个很好的做法。

无论如何，我想鼓励您将日志记录部分提取到一个方法中，并通过一些伪造的凭据对其进行测试：更简单、更好的设计：类似于

def myfunc(self):

    new_credentials = {}
    client = Client(
        username=self.username,
        password=self.password,
        auth_url=self.auth_url,
        user_domain_name=self.user_domain_name,
        domain_name=self.domain_name
    )

    abc = CredentialManager(client)

    for credential in abc.list():
        self.process_credential(credential, new_credentials)

@staticmethod
def process_credential(credential, cache):
    (access, secret) = _anotherfunc(credential.blob)
    defg = str(credential.type)
    MyClass.logging_credential_process(credential, not defg, defg in cache)
    cache[defg] = (access, secret)

@staticmethod
def logging_credential_process(credential, void_type, duplicate):
    if void_type:
        LOGGER.warning('no abc')
    if duplicate:
        LOGGER.info('Ignoring duplate')

测试更简单，看起来更好。

在 Python unittest 中模拟和修补 keystoneclient

Mocking and patching keystoneclient in Python unittest

python

unit-testing

mocking

python-unittest

magicmock