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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Code

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 elements
11         random.shuffle(self.seq)
12         self.seq.sort()
13         self.assertEqual(self.seq, range(10))
14
15         # should raise an exception for an immutable sequence
16         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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Code

1 import unittest
2 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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Code

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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Code

1 if __name__ == "__main__":
2   import unittest
3   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_name
20         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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Code

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") == 1000
10
11     def combo_test1(self):
12         print "+++ Converting MMX to 2010"
13         assert self.cvt.convert_to_decimal("MMXX") == 2010
14
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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Code

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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Code

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], ed
14     print("Converting %s to %s..." % (input
15     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)