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

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

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 not the_element:
        recheck_the_element = is_element_visible(self, (By.ID, "kw"))
        time_now = datetime.now()
        if recheck_the_element:
            print "element appears."
            break
        # 此处超时时限设置为10秒
        elif (time_now - time_start).seconds > 10:
            print "element is invisible!"
            break
        else:
            continue