自动化测试——Selenium+Python判断元素是否可见，及元素未出现时设置超时时限

自动化测试中，有时可以根据某元素是否出现（即可见）来进行断言，判断元素是否可见的方法如下：

from selenium.webdriver.support import expected_conditions as EC

def is_element_visible(self, element):
    driver = self.driver
    try:
        the_element = EC.visibility_of_element_located(element)
        assert the_element(driver)
        flag = True
    except:
        flag = False
    return flag

需要进行判断时，调用此方法即可。

有时在进行操作后，某元素需要一段时间后才能显示，此时可以设置一时间限制，在此时间间隔内不断判断该元素是否可见，若找到则继续后续操作，否则提示元素未找到。代码如下：

from selenium.webdriver.common.by import By
from datetime import datetime

the_element = is_element_visible(self, (By.ID, "kw"))
if the_element:
    print "element appears."
else:
    time_start = datetime.now()
    while True:
        time_now = datetime.now()
        time_difference = (time_now - time_start).seconds
        if time_difference < 60:
            recheck_the_element = is_element_visible(self, (By.ID, "kw"))
            if recheck_the_element:
                print "element appears."
                break
            else:
                continue
        else:
            print "element not appears."