unittest测试框架之assert断言

python内部自带了一个单元测试的模块，pyUnit也就是我们说的：unittest

 

先介绍下unittest的基本使用方法：

1.import unittest
2.定义一个继承自unittest.TestCase的测试用例类
3.定义setUp和tearDown，在每个测试用例前后做一些辅助工作。
4.定义测试用例，名字以test开头。
5.一个测试用例应该只测试一个方面，测试目的和测试内容应很明确。主要是调用assertEqual、assertRaises等断言方法判断程序执行结果和预期值是否相符。
6.调用unittest.main()启动测试
7.如果测试未通过，会输出相应的错误提示。如果测试全部通过则不显示任何东西，这时可以添加-v参数显示详细信息。

下面看具体的代码应用：

首先写了一个简单应用：

import random
import unittest

class TestSequenceFunctions(unittest.TestCase):

   def setUp(self):
       self.seq = 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, 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_error(self):
          element = random.choice(self.seq)
          self.assertTrue(element not in self.seq)


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

 下面是写了一个简单的应用，测试下面4个网址返回的状态码是否是200。

import unittest
import urllib

class TestUrlHttpcode(unittest.TestCase):
   def setUp(self):
       urlinfo = ['http://www.baidu.com','http://www.163.com','http://www.sohu.com','http://www.cnpythoner.com']
       self.checkurl = urlinfo

   def test_ok(self):
       for m in self.checkurl:
           httpcode = urllib.urlopen(m).getcode()
           self.assertEqual(httpcode,200)

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

 如果有的网址打不开，返回404的话,测试则会报错

 如果有的网址打不开，返回404的话,测试则会报错

  ERROR: test_ok (__main__.TestUrlHttpcode)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "jay.py", line 12, in test_ok
    httpcode = urllib.urlopen(m).getcode()
  File "/usr/lib/python2.7/urllib.py", line 86, in urlopen
    return opener.open(url)
  File "/usr/lib/python2.7/urllib.py", line 207, in open
    return getattr(self, name)(url)
  File "/usr/lib/python2.7/urllib.py", line 462, in open_file
    return self.open_local_file(url)
  File "/usr/lib/python2.7/urllib.py", line 476, in open_local_file
    raise IOError(e.errno, e.strerror, e.filename)
IOError: [Errno 2] No such file or directory: 'fewfe.com'

----------------------------------------------------------------------
Ran 1 test in 1.425s

FAILED (errors=1)
 

也有其他的unittest方法，用于执行更具体的检查，如：

Method     Checks that     New in
assertAlmostEqual(a, b)     round(a-b, 7) == 0      
assertNotAlmostEqual(a, b)     round(a-b, 7) != 0      
assertGreater(a, b)     a > b     2.7
assertGreaterEqual(a, b)     a >= b     2.7
assertLess(a, b)     a < b     2.7
assertLessEqual(a, b)     a <= b     2.7
assertRegexpMatches(s, re)     regex.search(s)     2.7
assertNotRegexpMatches(s, re)     not regex.search(s)     2.7
assertItemsEqual(a, b)     sorted(a) == sorted(b) and works with unhashable objs     2.7
assertDictContainsSubset(a, b)     all the key/value pairs in a exist in b     2.7
assertMultiLineEqual(a, b)     strings     2.7
assertSequenceEqual(a, b)     sequences     2.7
assertListEqual(a, b)     lists     2.7
assertTupleEqual(a, b)     tuples     2.7
assertSetEqual(a, b)     sets or frozensets     2.7
assertDictEqual(a, b)     dicts     2.7
assertMultiLineEqual(a, b)     strings     2.7
assertSequenceEqual(a, b)     sequences     2.7
assertListEqual(a, b)     lists     2.7
assertTupleEqual(a, b)     tuples     2.7
assertSetEqual(a, b)     sets or frozensets     2.7
assertDictEqual(a, b)     dicts     2.7

你可以用unittest模块的更多方法来做自己的单元测试。