Python中unittest用法实例

本文实例讲述了Python中unittest的用法，分享给大家供大家参考。具体用法分析如下：

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:
① setup():每个测试函数运行前运行
② teardown():每个测试函数运行完后执行
③ setUpClass():必须使用@classmethod 装饰器,所有test运行前运行一次
④ 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()

3.运行方式:在命令行直接运行这个runtest.py

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:
① @unittest.skip(reason):无条件跳过测试，reason描述为什么跳过测试
② @unittest.skipif(conditition,reason):condititon为true时跳过测试
③ @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

希望本文所述对大家Python程序设计的学习有所帮助。