前言：
装饰器其实就是一个以函数作为参数并返回一个替换函数的可执行函数
上一篇讲到用装饰器解决异常后自动截图，不过并没有与unittest结合，这篇把截图的装饰器改良了下，可以实现用例执行失败自动截图。
一、不带变量的装饰器
1.参考资料：http://www.artima.com/weblogs/viewpost.jsp?thread=240845，这里这篇讲的很好，可以看下原文
2.这个是不带变量的装饰器__init__里是初始化参数，__call__里面是原函数参数
Decorators without Arguments
If we create a decorator without arguments, the function to be decorated is passed to the constructor, and the __call__() method is called whenever the decorated function is invoked:
class decoratorWithoutArguments(object):
def __init__(self, f):
"""
If there are no decorator arguments, the function
to be decorated is passed to the constructor.
"""
print "Inside __init__()"
self.f = f
def __call__(self, *args):
"""
The __call__ method is not called until the
decorated function is called.
"""
print "Inside __call__()"
self.f(*args)
print "After self.f(*args)"
@decoratorWithoutArguments
def sayHello(a1, a2, a3, a4):
print ‘sayHello arguments:‘, a1, a2, a3, a4
二、带变量的装饰器
1.这个是带变量的参数，参数写到__init__里
Decorators with Arguments
Now let‘s modify the above example to see what happens when we add arguments to the decorator:
class decoratorWithArguments(object):
def __init__(self, arg1, arg2, arg3):
"""
If there are decorator arguments, the function
to be decorated is not passed to the constructor!
"""
print "Inside __init__()"
self.arg1 = arg1
self.arg2 = arg2
self.arg3 = arg3
def __call__(self, f):
"""
If there are decorator arguments, __call__() is only called
once, as part of the decoration process! You can only give
it a single argument, which is the function object.
"""
print "Inside __call__()"
def wrapped_f(*args):
print "Inside wrapped_f()"
print "Decorator arguments:", self.arg1, self.arg2, self.arg3
f(*args)
print "After f(*args)"
return wrapped_f
@decoratorWithArguments("hello", "world", 42)
def sayHello(a1, a2, a3, a4):
print ‘sayHello arguments:‘, a1, a2, a3, a4
三、截图装饰器
1.有了上面的参考文档，依着葫芦画瓢就行，最大的麻烦就是driver参数处理，这里放到__init__里就可以了
四、参考案例
# coding:utf-8
from selenium import webdriver
class Screen(object):
u‘‘‘这个应该截图功能的装饰器‘‘‘
def __init__(self, driver):
self.driver = driver
def __call__(self, f):
def inner(*args):
try:
return f(*args)
except:
import time
nowTime = time.strftime("%Y_%m_%d_%H_%M_%S")
self.driver.get_screenshot_as_file(‘%s.jpg‘ % nowTime)
raise
return inner
# 以下是装饰器与unittest结合的案例
import unittest
class Test(unittest.TestCase):
driver = webdriver.Firefox() # 全局参数driver
def setUp(self):
self.driver.get("https://www.baidu.com")
@Screen(driver)
def test01(self):
u‘‘‘这个是失败的案例‘‘‘
self.driver.find_element_by_id("11kw").send_keys("python")
self.driver.find_element_by_id("su").click()
@Screen(driver)
def test_02(self):
u‘‘‘这个是通过的案例‘‘‘
self.driver.find_element_by_id("kw").send_keys("yoyo")
self.driver.find_element_by_id("su").click()
def tearDown(self):
self.driver.quit()
if __name__ == "__main__":
unittest.main()
Selenium2+python自动化67-用例失败自动截图【转载】
原文：http://www.cnblogs.com/caoj/p/7815751.html