使用PYTHON的UNITTEST做测试

在练习的时候遇到问题， 在test.py中 用unittest.main(),不能找到测试函数。原因：测试函数必须要以小写的test开头，unittet才能找到。

顺便找到些好的帖子，收藏http://www.cnblogs.com/imouren/archive/2011/08/04/2127997.html

文档地址http://docs.python.org/library/unittest.html

第一个例子直接引用文档中的例子，其他的简略的写了写结论性的东西，具体的参考python_testing_cookbook一书。

一、简单的例子

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 1 import random 2 import unittest 3  4 class TestSequenceFunctions(unittest.TestCase): 5  6     def setUp(self): 7         self.seq = range(10) 8  9     def test_shuffle(self):10         # make sure the shuffled sequence does not lose any elements11         random.shuffle(self.seq)12         self.seq.sort()13         self.assertEqual(self.seq, range(10))14 15         # should raise an exception for an immutable sequence16         self.assertRaises(TypeError, random.shuffle, (1,2,3))17 18     def test_choice(self):19         element = random.choice(self.seq)20         self.assertTrue(element in self.seq)21 22     def test_sample(self):23         with self.assertRaises(ValueError):24             random.sample(self.seq, 20)25         for element in random.sample(self.seq, 5):26             self.assertTrue(element in self.seq)27 28 if __name__ == '__main__':29     unittest.main()

实现一个继承unittest.TestCase的类，使用unittest.main()来测试该类中所有以test开头的测试用例。

简单的assert方法有如下：
self.assertEquals(100, value)
self.assertTrue(value == 0)
self.assertFalse(value > 0
self.assertRaises(TypeError, value.convert_to_decimal)

在写测试用例的时候尽量使用assertEquals而不是assertTrue、assertFalse，当assertEquals失败的时候，会打印出比较的两方值更直观

self.fail([msg])会无条件的导致测试失败，不推荐使用。

下面的例子的写法是要避免发生：

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1 import unittest2 class BadTest(unittest.TestCase):3   def test_no_roman_numeral(self):4     value = RomanNumeralConverter(None)5     try:6       value.convert_to_decimal()7       self.fail("Expected a TypeError")8     except TypeError, e:9       pass

这个时候推推荐使用assertRaises

二、使用setUp和tearDown

每次运行test方法时，先用setUp初始化程序，然后运行test方法，最后使用tearDown清理程序
def setUp(self):
    print "Creating a new RomanNumeralConverter..."
    self.cvt = RomanNumeralConverter()

def tearDown(self):
    print "Destroying the RomanNumeralConverter..."
    self.cvt = None

如果不同的方法需要不同的setUp和tearDown方法，那么只好写过个测试用例了。

三、使用比unittest.main()更详细的运行测试用例的方法

if __name__ == "__main__":
  suite = unittest.TestLoader().loadTestsFromTestCase( \
                 RomanNumeralConverterTest)
  unittest.TextTestRunner(verbosity=2).run(suite）

python使用unittest.TestLoader().loadTestsFromTestCase方法获取RomanNumeralConverterTest的所有test方法
然后通过TextTestRunner来运行

四、运行部分测试方法

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 1 if __name__ == "__main__": 2   import sys 3   suite = unittest.TestSuite() 4   if len(sys.argv) == 1: 5     suite = unittest.TestLoader().loadTestsFromTestCase(\ 6                   RomanNumeralConverterTest) 7   else: 8     for test_name in sys.argv[1:]: 9       suite.addTest(\10         RomanNumeralConverterTest(test_name))11   unittest.TextTestRunner(verbosity=2).run(suite)

五、一次运行多个测试用例

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1 if __name__ == "__main__":2   import unittest3   from recipe5 import *4   suite1 = unittest.TestLoader().loadTestsFromTestCase( \5                  RomanNumeralConverterTest)6   suite2 = unittest.TestLoader().loadTestsFromTestCase( \7                  RomanNumeralComboTest)8   suite = unittest.TestSuite([suite1, suite2])9   unittest.TextTestRunner(verbosity=2).run(suite)

六、在test model 中 使用test suites

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 1 def high_and_low(): 2     suite = unittest.TestSuite() 3     suite.addTest(\ 4        RomanNumeralConverterTest("test_parsing_millenia")) 5     suite.addTest(\ 6        RomanNumeralConverterTest("test_parsing_one")) 7     return suite 8  9 def combos():10     return unittest.TestSuite(map(RomanNumeralConverterTest,\11               ["test_combo1", "test_combo2", "test_combo3"]))12 13 def all():14     return unittest.TestLoader().loadTestsFromTestCase(\15                                RomanNumeralConverterTest)16 17 if __name__ == "__main__":18     for suite_func in [high_and_low, combos, all]:19         print "Running test suite '%s'" % suite_func.func_name20         suite = suite_func()21         unittest.TextTestRunner(verbosity=2).run(suite)

七、将已有的测试代码迁移到unittest

不使用unittest

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 1 from recipe7 import * 2  3 class RomanNumeralTester(object): 4     def __init__(self): 5         self.cvt = RomanNumeralConverter() 6  7     def simple_test(self): 8         print "+++ Converting M to 1000" 9         assert self.cvt.convert_to_decimal("M") == 100010 11     def combo_test1(self):12         print "+++ Converting MMX to 2010"13         assert self.cvt.convert_to_decimal("MMXX") == 201014 15     def combo_test2(self):16         print "+++ Converting MMMMDCLXVIII to 4668"17         val = self.cvt.convert_to_decimal("MMMMDCLXVII")18         self.check(val, 4668)19 20     def other_test(self):21         print "+++ Converting MMMM to 4000"22         val = self.cvt.convert_to_decimal("MMMM")23         self.check(val, 4000)24 25     def check(self, actual, expected):26         if (actual != expected):27             raise AssertionError("%s doesn't equal %s" % \28                     (actual, expected))29 30     def test_the_system(self):31         self.simple_test()32         self.combo_test1()33         self.combo_test2()34         self.other_test()35 36 if __name__ == "__main__":37     tester = RomanNumeralTester()38     tester.test_the_system()

迁移到unittest

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 1 from recipe7 import * 2 from recipe7_legacy import * 3 import unittest 4  5 if __name__ == "__main__": 6     tester = RomanNumeralTester() 7  8     suite = unittest.TestSuite() 9     for test in [tester.simple_test, tester.combo_test1, \10                  tester.combo_test2, tester.other_test]:11         testcase = unittest.FunctionTestCase(test)12         suite.addTest(testcase)13 14     unittest.TextTestRunner(verbosity=2).run(suite)

八、简单化

一个测试函数里面写一个assert***,便于查看bug

九、测试边缘

比如测试一个到4000为止的整数，需要测试
1,4000, 0 4001, -1, None, 1.2
错误的输入也是必要的

通过迭代测试边缘

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 1 def test_bad_inputs(self): 2     r = self.cvt.convert_to_roman 3     d = self.cvt.convert_to_decimal 4     edges = [("equals", r, "", None),\ 5          ("equals", r, "I", 1.2),\ 6          ("raises", d, TypeError, None),\ 7          ("raises", d, TypeError, 1.2)\ 8         ] 9     [self.checkout_edge(edge) for edge in edges]10 11 def checkout_edge(self, edge):12   if edge[0] == "equals":13     f, output, input = edge[1], edge[2], ed14     print("Converting %s to %s..." % (input15     self.assertEquals(output, f(input))16   elif edge[0] == "raises":17     f, exception, args = edge[1], edge[2], 18     print("Converting %s, expecting %s" % \19                     (args, exception))20     self.assertRaises(exception, f, *args)