web通常包含了Hyper Text Markup Language (HTML)、Cascading Style Sheets (CSS)和JavaScript。本節主要內容如下：
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瞭解更多Selenium webDriver查找元素的知識
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使用各種瀏覽器提供的開發工具找到和定位元素
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多種發現元素的方法：ID、Name、類屬性值、XPath、CSS選擇器
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Selenium webDriver中的各種find_element_by方法。
一般的瀏覽器都有查看源碼的功能 。
使用開發工具發現定位器
Firefox的插件Firebug是個好幫手，可以F12或者右鍵點擊元素選擇“Inspect Element with Firebug”打開。Firefox的搜素框還可以對XPath或CSS進行查找。
Chrome中可以F12或者右鍵點擊元素選擇“Inspect Element”的方式查看代碼。查找功能也和Firefox類似。Internet Explorer也有類似功能，不再贅述。
元素查找
find_element_by*系列方法在找到元素的時候返回WebElement實例，否則產生NoSuchElementException異常。另外find_elements_by*系列方法可以一次返回多個元素。
driver.find_element_by_css_selector(‘#search’)
| Method | Description | Argument | Example |
| find_element_by_id(id) | This method finds an element by the ID attribute value | id: The ID of the element to be found | driver.find_element_by_id(‘search’) |
| find_element_by_name(name) | This method finds an element by the name attribute value | name: The name of the element to be found | driver.find_element_by_name(‘q’) |
| find_element_by_class_name(name) | This method finds an element by the class attribute value | name: The class name of the element to be found | driver.find_element_by_class_name(‘input-text’) |
| find_element_by_tag_name(name) | This method finds an element by its tag name | name: The tag name of the element to be found | driver.find_element_by_tag_name(‘input’) |
| find_element_by_xpath(xpath) | This method finds an element using XPath | xpath: The xpath of the element to be found | driver.find_element_by_xpath(‘form[0]/div[0]/input[0]’) |
| find_element_by_css_selector(css_selector) | This method finds an element by the CSS selector | css_selector: The CSS selector of the element to be found | |
| find_element_by_link_text(link_text) | This method finds an element by the link text | link_text: The text of the element to be found | driver.find_element_by_link_text(‘Log In’) |
| find_element_by_partial_link_text(link_text) | This method finds an element by a partial match of its link text | link_text: The text to match part of the text of the element | driver.find_element_by_partial_link_text(‘Log’) |
通過id、name、類屬性是最建議，也是最快速的查找方法，尤其是id和name。其次使用tag和鏈接文本，萬不得已才使用xpath和css。
XPath即爲XML路徑語言（XML Path Language），它是一種用來確定XML文檔中某部分位置的語言。參考：XPath維基百科介紹 以及w3schools的Xpath介紹，zvon的XPath 1.0介紹。參考書籍：Selenium Testing Tools Cookbook。注意XPath的速度會比CSS還慢，不過支持向前向後定義和相對路徑。
層疊樣式表（英語：Cascading Style Sheets，簡寫CSS），又稱串樣式列表、層次結構式樣式表文件，一種用來爲結構化文檔（如HTML文檔或XML應用）添加樣式（字體、間距和顏色等）的計算機語言。參考CSS維基百科介紹，w3schools之CSS介紹 和
實例
import unittest
from selenium import webdriver
class HomePageTest(unittest.TestCase):
@classmethod
def setUpClass(cls):
# create a new Firefox session
cls.driver = webdriver.Firefox()
cls.driver.implicitly_wait(30)
cls.driver.maximize_window()
# navigate to the application home page
cls.driver.get('http://demo-store.seleniumacademy.com/')
def test_search_text_field_max_length(self):
# get the search textbox
search_field = self.driver.find_element_by_id('search')
# check maxlength attribute is set to 128
self.assertEqual('128', search_field.get_attribute('maxlength'))
def test_search_button_enabled(self):
# get Search button
search_button = self.driver.find_element_by_class_name('button')
# check Search button is enabled
self.assertTrue(search_button.is_enabled())
def test_my_account_link_is_displayed(self):
# get the Account link
account_link = self.driver.find_element_by_link_text('ACCOUNT')
# check My Account link is displayed/visible in the Home page footer
self.assertTrue(account_link.is_displayed())
def test_account_links(self):
# get the all the links with Account text in it
account_links = self.driver.\
find_elements_by_partial_link_text('ACCOUNT')
# check Account and My Account link is displayed/visible in the Home page footer
self.assertTrue(len(account_links), 2)
def test_count_of_promo_banners_images(self):
# get promo banner list
banner_list = self.driver.find_element_by_class_name('promos')
# get images from the banner_list
banners = banner_list.find_elements_by_tag_name('img')
# check there are 3 banners displayed on the page
self.assertEqual(3, len(banners))
def test_vip_promo(self):
# get vip promo image
vip_promo = self.driver.\
find_element_by_xpath("//img[@alt='Shop Private Sales - Members Only']")
# check vip promo logo is displayed on home page
self.assertTrue(vip_promo.is_displayed())
# click on vip promo images to open the page
vip_promo.click()
# check page title
self.assertEqual("VIP", self.driver.title)
def test_shopping_cart_status(self):
# check content of My Shopping Cart block on Home page
# get the Shopping cart icon and click to open the Shopping Cart section
shopping_cart_icon = self.driver.\
find_element_by_css_selector('div.header-minicart span.icon')
shopping_cart_icon.click()
# get the shopping cart status
shopping_cart_status = self.driver.\
find_element_by_css_selector('p.empty').text
self.assertEqual('You have no items in your shopping cart.',
shopping_cart_status)
# close the shopping cart section
close_button = self.driver.\
find_element_by_css_selector('div.minicart-wrapper a.close')
close_button.click()
@classmethod
def tearDownClass(cls):
# close the browser window
cls.driver.quit()
if __name__ == '__main__':
unittest.main(verbosity=2)# python homepagetest.py
test_account_links (__main__.HomePageTest) ... ok
test_count_of_promo_banners_images (__main__.HomePageTest) ... ok
test_my_account_link_is_displayed (__main__.HomePageTest) ... ok
test_search_button_enabled (__main__.HomePageTest) ... ok
test_search_text_field_max_length (__main__.HomePageTest) ... ok
test_shopping_cart_status (__main__.HomePageTest) ... ok
test_vip_promo (__main__.HomePageTest) ... ok
----------------------------------------------------------------------
Ran 7 tests in 77.086s
OK
