单元测试框架之unittest(五)

一、摘要

单元测试里很重要的一个部分就是断言，unittest为我们提供了很多断言方法，断言方法分为三类，一种是用来断言被测试的方法的，另一种是测试是否抛正确异常的，第三种是用来断言日志是否包含应有信息的，方法很多

第一种很好理解，是用来判断我们的被测点是否达到预期用的。

第二种用来判断在某种情况下是否会抛出特定的异常，如果会抛出该特定异常，则会判断为断言成功，如果没抛出这种特定异常则会判断为断言失败。

第三种是用来断言日志是否包含应有信息的

assertEqual(a, b, msg=None)断言 a == b
assertNotEqual(a, b, msg=None)断言  a != b
assertTrue(expr, msg=None)断言  bool(expr) is True
assertFalse(expr, msg=None)断言  bool(expr) is False
assertIs(a, b, msg=None)断言  a is b
assertIsNot(a, b, msg=None)断言  a is not b
assertIsNone(expr, msg=None)断言  expr is None
assertIsNotNone(expr, msg=None)断言  expr is not None
assertIn(a, b, msg=None)断言  a in b
assertNotIn(a, b, msg=None)断言  a not in b
assertIsInstance(obj, cls, msg=None)断言 obj  is cls instance
assertNotIsInstance(obj, cls, msg=None)断言 obj is not cls instance
assertRaises(exc, fun, *args, **kwds)断言  fun(*args, **kwds) 是否抛出正确异常， 否则抛出断言异常
assertRaisesRegex(exc, r, fun, *args, **kwds) 断言  fun(*args, **kwds) 是否抛出正确异常，同时可以用正则r去匹配异常信息exc，否则抛出断言异常
assertWarns(warn, fun, *args, **kwds)断言fun(*args, **kwds) raises warn
assertWarnsRegex(warn, r, fun, *args, **kwds)断言  fun(*args, **kwds) raises warn and the message matches regex r
assertLogs(logger, level) 断言log： 断言log里是否出现期望的信息，如果出现则通过，如果没出现，则断言失败抛出断言异常
assertAlmostEqual(a, b, msg=None, delta=None) round(a-b, 7) == 0  断言a-b约等于0，小数点后默认保留7位
assertNotAlmostEqual(a, b, msg=None, delta=None) round(a-b, 7) != 0 断言不是约等于的情况
assertGreater(a, b, msg=None) a > b  断言大于
assertGreaterEqual(a, b, msg=None) a >= b  断言大于等于
assertLess(a, b, msg=None, msg=None) a < b  断言小于
assertLessEqual(a, b, msg=None) a <= b 断言小于等于
assertRegex(text, regex, msg=None) r.search(s)
assertNotRegex(text, regex, msg=None) not r.search(s)
assertCountEqual(a, b, msg=None) a and b have the same elements in the same number, regardless of their order
assertMultiLineEqual(a, b, msg=None) strings 断言多行字符串
assertSequenceEqual(a, b, msg=None, seq_type=None) sequences 断言序列
assertListEqual(a, b, msg=None) lists 断言List
assertTupleEqual(a, b, msg=None) tuples  断言元组
assertSetEqual(a, b, msg=None) sets or frozensets 断言Set
assertDictEqual(a, b, msg=None) dicts 断言词典

在早期的python版本中，断言函数的写法有些已经被废弃了，如下对应关系所示，在我们使用编译器的时候经常会提示“Deprecated”这个单词，意味着有新的方式取代了当前的实现方法

Method Name             Deprecated alias         Deprecated alias
assertEqual()           failUnlessEqual          assertEquals
assertNotEqual()        failIfEqual              assertNotEquals
assertTrue()            failUnless               assert_
assertFalse()           failIf
assertRaises()          failUnlessRaises
assertAlmostEqual()     failUnlessAlmostEqual    assertAlmostEquals
assertNotAlmostEqual()  failIfAlmostEqual        assertNotAlmostEquals
assertRegex()           assertRegexpMatches
assertNotRegex()        assertNotRegexpMatches
assertRaisesRegex()     assertRaisesRegexp

二、代码实例

# encoding = utf-8
import unittest
import random
import logging

mylogger = logging.Logger('TestToBeTest')

#  被测试类
class ToBeTest(object):
    @classmethod
    def sum(cls, a, b):
        return a + b

    @classmethod
    def div(cls, a, b):
        return a/b

    @classmethod
    def return_none(cls):
        return None

#  单元测试类
class TestToBeTest(unittest.TestCase):

    # assertEqual()方法实例
    def test_assertequal(self):
        try:
            a, b = 100, 200
            sum = 300
            # 断言a+b等于sum
            self.assertEqual(a + b, sum, '断言失败，%s+%s != %s ' %(a, b, sum))
        except AssertionError as e:
            print(e)
        # 断言log
        with self.assertLogs('assertlog', level='INFO') as cm:
            logging.getLogger('assertlog').info('first message')
            logging.getLogger('assertlog.bar').error('second message')
        self.assertEqual(cm.output, ['INFO:assertlog:first message', 'ERROR:assertlog.bar:second message'])

    # assertNotEqual()方法实例
    def test_assertnotequal(self):
        try:
            a, b = 100, 200
            res = -1000
            # 断言a-b不等于res
            self.assertNotEqual(a - b, res, '断言失败，%s-%s != %s ' %(a, b, res))
        except AssertionError as e:
            print(e)

    # assertTure()方法实例
    def test_asserttrue(self):
        list1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
        list2 = [10, 9, 8, 7, 6, 5, 4, 3, 2, 1]
        list3 = list1[::-1]
        print(list3)
        try:
            # 断言表达式为真
            self.assertTrue(list3 == list2, "表达式为假")
        except AssertionError as e:
            print(e)

    # assertFalse()方法实例
    def test_assertfalse(self):
        list1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
        list2 = [10, 9, 8, 7, 6, 5, 4, 3, 2, 1]
        list3 = list1[::-1]
        try:
            #  断言表达式为假
            self.assertFalse(list3 == list1, "表达式为真")
        except AssertionError as e:
            print(e)

    # assertIs()方法实例
    def test_assertis(self):
        list1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
        list2 = list1
        try:
            # 断言list2和list1属于同一个对象
            self.assertIs(list1, list2, "%s 与 %s 不属于同一对象" % (list1, list2))
        except AssertionError as e:
            print(e)

    # assertIsNot()方法实例
    def test_assertisnot(self):
        list1 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
        list2 = [10, 9, 8, 7, 6, 5, 4, 3, 2, 1]
        try:
            # 断言list2和list1不属于同一个对象
            self.assertIsNot(list2, list1, "%s 与 %s 属于同一对象" % (list1, list2))
        except AssertionError as e:
            print(e)

    # assertIsNone()方法实例
    def test_assertisnone(self):
        try:
            results = ToBeTest.return_none()
            # 断言表达式结果是none
            self.assertIsNone(results, "is not none")
        except AssertionError as e:
            print(e)

    # assertIsNotNone()方法实例
    def test_assertisnotnone(self):
        try:
            results = ToBeTest.sum(4, 5)
            # 断言表达式结果不是none
            self.assertIsNotNone(results, "is none")
        except AssertionError as e:
            print(e)

    # assertIn()方法实例
    def test_assertin(self):
        try:
            str1 = "this is unit test demo"
            str2 = "demo"
            # 断言str2包含在str1中
            self.assertIn(str2, str1, "%s 不被包含在 %s中" %(str2, str1))
        except AssertionError as e:
            print(e)

    # assertNotIn()方法实例
    def test_assertnotin(self):
        try:
            str1 = "this is unit test demo"
            str2 = "ABC"
            # 断言str2不包含在str1中
            self.assertNotIn(str2, str1, "%s 包含在 %s 中" % (str2, str1))
        except AssertionError as e:
            print(e)

    # assertIsInstance()方法实例
    def test_assertisinstance(self):
        try:
            o = ToBeTest
            k = object
            # 断言测试对象o是k的类型
            self.assertIsInstance(o, k, "%s的类型不是%s" % (o, k))
        except AssertionError as e:
            print(e)

    # assertNotIsInstance()方法实例
    def test_assertnotisinstance(self):
        try:
            o = ToBeTest
            k = int
            # 断言测试对象o不是k的类型
            self.assertNotIsInstance(o, k, "%s 的类型是%s" % (o, k))
        except AssertionError as e:
            print(e)

    # assertRaises()方法实例
    def test_assertraises(self):
        # 测试抛出指定的异常类型
        # assertRaises(exception)
        with self.assertRaises(TypeError) as exc:
            random.sample([1, 2, 3, 4, 5, 6], "j")
        # 打印详细的异常信息
        print(exc.exception)
        # assertRaises(exception, callable, *args, **kwds)
        try:
            self.assertRaises(ZeroDivisionError, ToBeTest.div, 3, 0)
        except ZeroDivisionError as e:
            print(e)

    # assertRaisesRegexp()方法实例
    def test_assertraisesregex(self):
        # 测试抛出指定的异常类型，并用正则表达式去匹配异常信息
        # assertRaisesRegex(exception, regexp)
        with self.assertRaisesRegex(ValueError, "literal") as exc:
            int("abc")
        # 打印详细的异常信息
        print(exc.exception)

        # assertRaisesRegex(exception, regexp, callable, *args, **kwds)
        try:
            self.assertRaisesRegex(ValueError, 'invalid literal for.*\'abc\'$', int, 'abc')
        except AssertionError as e:
            print(e)

    # assertLogs()方法实例
    def test_assertlogs(self):
        with self.assertLogs(mylogger) as log:
            mylogger.error("打开浏览器")
            mylogger.info('关闭并退出浏览器')
            self.assertEqual(log.output, ['ERROR:TestToBeTest:打开浏览器', 'INFO:TestToBeTest:关闭并退出浏览器'])

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

三、代码解析