selenium webdriver在IE中测试，需要IEDriverServer支持,IEDriverServer下载地址如下
 http://docs.seleniumhq.org/download/
selenium webdriver在chrome中测试, 需要chromeDriver支持,chromeDriver下载地址如下
 https://code.google.com/p/chromedriver/
下载到本地后，在测试类setUp方法中指定相应driver的本地地址，并实例化相应的driver类，示例代码如下:

......

	class HouseTest(unittest.TestCase):

		def firefox(self):
			driver = webdriver.Firefox()
			return driver

		def ie(self):
			iedriver = "C:\\Program Files\\Internet Explorer\\IEDriverServer.exe"
			os.environ["webdriver.ie.driver"] = iedriver
			driver = webdriver.Ie(iedriver)
			return driver

		def chrome(self):
			chromedriver = "C:\\Users\\pc\\AppData\\Local\\Google\\Chrome\\Application\\chromedriver.exe"
			os.environ["webdriver.chrome.driver"] = chromedriver
			driver = webdriver.Chrome(chromedriver)
			return driver

		def setUp(self):

			browser = {
					'ie' : lambda : self.ie(),
					'firefox' : lambda : self.firefox(),
					'chrome' : lambda : self.chrome()
					}
			
			self.driver = browser['ie']()
#			self.driver = browser['chrome']()
#			self.driver = browser['firefox']()
......