47-文档测试（1）

文档测试：

Python内置的“文档测试”（doctest）模块可以直接提取注释中的代码并执行测试。

mydict2.py

class Dict(dict): #下面这些'''xxx'''部分即为自定义的测试语句，写成了注释。
'''
Simple dict but also support access as x.y style.

>>> d1 = Dict()
>>> d1['x'] = 100
>>> d1.x
100
>>> d1.y = 200
>>> d1['y']
200
>>> d2 = Dict(a=1, b=2, c='3')
>>> d2.c
'3'
>>> d2['empty']
Traceback (most recent call last):
...
KeyError: 'empty'
>>> d2.empty
Traceback (most recent call last):
...
AttributeError: 'Dict' object has no attribute 'empty'
'''
def init(self, kw):
super(Dict, self).init(kw)

def getattr(self, key):
try:
return self[key]
except KeyError:
raise AttributeError(r"'Dict' object has no attribute '%s'" % key)

def setattr(self, key, value):
self[key] = value

if name=='main': #当且仅当运行 {mydict2}时，才发生if后面的语句
import doctest
doctest.testmod()

若没有任何输出，说明测试通过,否则就是有错误