概述
简介
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
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()
最后
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