Python+Selenium之expected_conditi

文件位置：（Python安装位置）E:\Python27\Lib\site-packages\selenium\webdriver\support

简介：expected_conditions一般也简称EC，咱们看着源码一个个分析用离子来分析其具体作用

1.title_is

1.1 源码

class title_is(object):
    """An expectation for checking the title of a page.
    title is the expected title, which must be an exact match
    returns True if the title matches, false otherwise."""
    #检查页面的title与期望值是都完全一致，如果完全一致，返回Ture,否则返回Flase
    def __init__(self, title):
        self.title = title

    def __call__(self, driver):
        return self.title == driver.title

1.2 作用

检查页面的title与期望值是都完全一致，如果完全一致，返回True,否则返回Flase

1.3 实例用法

#coding=utf-8

from selenium import webdriver
from selenium.webdriver.support import expected_conditions as EC

driver=webdriver.Firefox()
driver.get('https://www.jianshu.com/u/00578e97e968')
title=EC.title_is(u'路由心定 - 简书')
print title(driver)

2.title_contains

2.1 源码

class title_contains(object):
    """ An expectation for checking that the title contains a case-sensitive
    substring. title is the fragment of title expected
    returns True when the title matches, False otherwise
    """
    def __init__(self, title):
        self.title = title

    def __call__(self, driver):
        return self.title in driver.title

2.2 作用

作用与title_is差不多，只不过这个是只要包含指定字符就可以

2.3 实例用法

#coding=utf-8

from selenium import webdriver
from selenium.webdriver.support import expected_conditions as EC

driver=webdriver.Firefox()
driver.get('https://www.jianshu.com/u/00578e97e968')
title1=EC.title_is(u'路由心定 - 简书')
title2=EC.title_contains(u'路由心定')
print title1(driver)
print title2(driver)

3.presence_of_element_located

3.1 源码

class presence_of_element_located(object):
    """ An expectation for checking that an element is present on the DOM
    of a page. This does not necessarily mean that the element is visible.
    locator - used to find the element
    returns the WebElement once it is located
    """
    def __init__(self, locator):
        self.locator = locator

    def __call__(self, driver):
        return _find_element(driver, self.locator)

3.2 作用

判断某个元素是否被加到了dom树里，并不代表该元素一定可见 ,通俗易懂点就是元素存不存在这个页面

3.3 实际用法

#coding=utf-8

from selenium import webdriver
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.by import By
from selenium.webdriver.support.wait import WebDriverWait

driver=webdriver.Firefox()
driver.get('https://www.jianshu.com/u/00578e97e968')
elem = WebDriverWait(driver, 10).until(EC.presence_of_element_located((By.XPATH, "/html/body/div[1]/div/div[1]/div[1]/div[1]/a")))
print elem

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