解决只打开一次浏览器，测试多条用例？

# _*_ encoding:utf-8 _*_

from selenium import webdriver
import unittest
import time

class login(unittest.TestCase):

 @classmethod
def setUpClass(cls):
cls.driver = webdriver.Firefox()
cls.driver.implicitly_wait(10)
cls.base_url = '网址'
cls.driver.get(cls.base_url)
print ("Will start SetUpClass,start Firefox.....")

def test_login_mlf(self):
driver = self.driver
driver.get(self.base_url)
driver.find_element_by_name("UserName").clear()
driver.find_element_by_name("UserName").send_keys("account")
driver.find_element_by_name("Password").clear()
driver.find_element_by_name("Password").send_keys("aa123456")
driver.find_element_by_css_selector(".btn.btn-primary.btn-lg.btn-block").click()
self.assertIsNotNone(driver.find_element_by_link_text("个人中心"))
print ("Test login.....")

def test_abc(self):
print ("Test abc.....")

 @classmethod
def tearDownClass(cls):
cls.driver.quit()
print ("Will stop tearDownClass,quit Firefox.....")

if __name__ == '__main__':
unittest.main()

.Will start SetUpClass,start Firefox.....
Test abc.....
.Test login.....

----------------------------------------------------------------------
Ran 2 tests in 12.226s

OK
Will stop tearDownClass,quit Firefox.....