@classmethod

from time import sleepimport unittestclass extest(unittest.TestCase):   '''def setUp(self):      print('test start')         def tearDown(self):      print('test end')'''   @classmethod   def setUpClass(cls):      print('开始执行用例...')   @classmethod   def tearDownClass(cls):      print('用例执行结束...')   def test1(self):      print('执行用例1...')   def test2(self):      print('执行用例2...')   def test3(self):      print('执行用例3...')      unittest.main()