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我有一个相当有趣的问题。我正在尝试模拟一个可以通过内部验证的类，并且在实例化时会返回一个 magicmock 实例。

例如，我有一个 pydantic 模型可以验证以下字段：

from typing import Type
from pydantic import BaseModel

class SomeClass:
    pass

class SubSomeClass(SomeClass):
    pass

class OtherClass:
    pass

class SomeModel(BaseModel):
    cls: Type[SomeClass]

# here I can put either `SomeClass` or its subclasses
validated_some = SomeModel(cls=SubSomeClass)

# this would cause ValidationError
SomeModel(cls=OtherClass)
"""
pydantic.error_wrappers.ValidationError: 1 validation error for SomeModel
cls
  subclass of SomeClass expected (type=type_error.subclass; expected_class=SomeClass)
"""

现在在我的测试中，我试图模拟我的SomeClassusing MagicMock，但我无法创建一个模拟的类对象，它就像SomeClass.

我尝试了以下方法：

>>> type(Mock(spec=SomeClass))
<class 'unittest.mock.Mock'> # doesn't pass validation

class MockSomeClass(SomeClass, MagicMock):
    """Mocked SomeClass"""

    def __init__(self, *args, **kwargs):
        pass

实例化时不返回MagicMock实例，即MockSomeClass()。

基本上我需要一些类似的东西：

>>> type(mocked_some_class)
<class 'type'>
>>> import inspect
>>> inspect.getmro(mocked_some_class)
(..., <class '__main__.SomeClass'>, ...)
>>> mocked_some_class()
<MagicMock id='...'>
4

1 回答 1

0

这是我最终做的事情：

from unittest.mock import Mock

class MockSomeClass(SomeClass, Mock):
    """Mocked SomeClass class"""

    def __new__(cls, *args, **kwargs):
        return MagicMock()

现在所有检查都通过了：

>>> type(MockSomeClass)
<class 'type'>

>>> inspect.getmro(MockSomeClass)
(<class '__main__.MockSomeClass'>, <class '__main__.SomeClass'>, <class 'unittest.mock.Mock'>, ...)

>>> MockSomeClass()
<MagicMock id='...'>

希望，它对某人有用！:)

于 2020-06-14T17:42:32.480 回答