Python unittest

1. unittest module包含了编写运行unittest的功能，自定义的test class都要集成unitest.TestCase类，test method要以test开头，运行顺序根据test method的名字排序，特殊方法:
   • setup():每个测试函数运行前运行
   • teardown():每个测试函数运行完后执行
   • setUpClass():必须使用@classmethod 装饰器,所有test运行前运行一次
   • tearDownClass():必须使用@classmethod装饰器,所有test运行完后运行一次
2. 示例代码:

   #文件名runtest.py
   import random
   import unittest
   
   class TestSequenceFunctions(unittest.TestCase):
   
       def setUp(self):
           self.seq = list(range(10))
   
       def test_shuffle(self):
           # make sure the shuffled sequence does not lose any elements
           random.shuffle(self.seq)
           self.seq.sort()
           self.assertEqual(self.seq, list(range(10)))
   
           # should raise an exception for an immutable sequence
           self.assertRaises(TypeError, random.shuffle, (1,2,3))
   
       def test_choice(self):
           element = random.choice(self.seq)
           self.assertTrue(element in self.seq)
   
       def test_sample(self):
           with self.assertRaises(ValueError):
               random.sample(self.seq, 20)
           for element in random.sample(self.seq, 5):
               self.assertTrue(element in self.seq)
   
   if __name__ == '__main__':
       unittest.main()

   运行方式:在命令行直接运行这个runtest.py
3. 可以使用unitest.skip装饰器族跳过test method或者test class,这些装饰器包括:
   • @unittest.skip(reason):无条件跳过测试，reason描述为什么跳过测试
   • @unittest.skipif(conditition,reason):condititon为true时跳过测试
   • @unittest.skipunless(condition,reason):condition不是true时跳过测试
   • 可以自定义skip decorator

     #这是一个自定义的skip decorrator
     def skipUnlessHasattr(obj, attr):
         if hasattr(obj, attr):
             return lambda func: func
         return unittest.skip("{!r} doesn't have {!r}".format(obj, attr))

   • skip decorator示例代码:

     class MyTestCase(unittest.TestCase):
     
         @unittest.skip("demonstrating skipping")
         def test_nothing(self):
             self.fail("shouldn't happen")
     
         @unittest.skipIf(mylib.__version__ < (1, 3),
                          "not supported in this library version")
         def test_format(self):
             # Tests that work for only a certain version of the library.
             pass
     
         @unittest.skipUnless(sys.platform.startswith("win"), "requires Windows")
         def test_windows_support(self):
             # windows specific testing code
             pass
     
     @unittest.skip("showing class skipping")
     class MySkippedTestCase(unittest.TestCase):
         def test_not_run(self):
             pass

4. expected failure:使用@unittest.expectedFailure装饰器，如果test失败了，这个test不计入失败的case数目