python - 在 Python 中测试抽象类

Question

我使用Python(2.7)中的抽象类创建了一个类，现在我想通过Nose测试这个类。技术上如何实现？

这里我给出一个示例代码:

# -*- coding: utf-8 -*-
from abc import ABCMeta, abstractmethod, abstractproperty


class A(object):

    __metaclass__ = ABCMeta

    @abstractproperty
    def a(self):
        pass

    @abstractmethod
    def do(self, obj):
        pass

Answer 1

您可以创建抽象类的子类并测试该子类。此外，您可以在调用抽象方法时引发 NotImplementedError，而不是 pass:

@abstractproperty
def a(self):
    raise NotImplementedError("Not implemented")

@abstractmethod
def do(self, obj):
    raise NotImplementedError("Not implemented")

如 Python exceptions documentation 中所述:

exception NotImplementedError

This exception is derived from RuntimeError. In user defined base classes, abstract methods should raise this exception when they require derived classes to override the method.

然后你实现一个子类:

class B(A):
    def a(self):
        super(B, self).a()
    
    def do(self, obj):
        super(B, self).do(obj)

你可以这样测试:

@raises(NotImplementedError)
def abstractPropertyAShouldNotRun():
    B().a()

@raises(NotImplementedError)
def abstractMethodDoShouldNotRun():
    obj = []
    B().do(obj)