Python断言方法:assert
转载地址:https://blog.csdn.net/qq_39247153/article/details/81082313
前言
在测试用例中,执行完测试用例后,最后一步是判断测试结果是pass还是fail,自动化测试脚本里面一般把这种生成测试结果的方法称为断言(assert)。
用unittest组件测试用例的时候,断言的方法还是很多的,下面介绍几种常用的断言方法:
assertEqual、assertIn、assertTrue
基本断言方法
基本的断言方法提供了测试结果是True还是False。所有的断言方法都有一个msg参数,如果指定msg参数的值,则将该信息作为失败的错误信息返回。
序号 | 断言方法 | 断言描述 |
1 | assertEqual(arg1, arg2, msg=None) | 验证arg1=arg2,不等则fail |
2 | assertNotEqual(arg1, arg2, msg=None) | 验证arg1!=arg2,相等则fail |
3 | assertTrue(expr, msg=None) | 验证expr是true,如果为false,则fail |
4 | assertFalse(expr, msg=None) |
验证expr是false,如果为true,则fail |
5 | assertIs(arg1, arg2, msg=None) |
验证arg1=arg2是同一个对象,不是则fail |
6 | assertIsNot(arg1, arg2, msg=None) | 验证arg1、arg2不是同一个对象,是则fail |
7 | assertIsNone(expr, msg=None) | 验证expr是None,不是则fail |
8 | assertIsNotNone(expr,msg=None) | 验证expr不是None,是则fail |
9 | assertIn(arg1, arg2, msg=None) | 验证arg1是arg2的子串,不是则fail |
10 | assertNotIn(arg1, arg2, msg=None) | 验证arg1不是arg2的子串,是则fail |
11 | assertIsInstance(obj, cls, msg=None) | 验证obj是cls的实例,不是则fail |
12 | assertNotIsInstance(obj, cls, msg=None) | 验证obj不是cls的实例,是则fail |
一、简单案例
1.下面写了4个case,其中第四个是执行失败的
# coding:utf-8
import unittest
class Test(unittest.TestCase):def test01(self):"'判断a == b'"a = 1b = 1self.assertEqual(a, b)def test02(self):"'判断a in b'"a = "hello"b = "hello world!"self.assertIn(a, b)def test03(self):"'判断a is True'"a = Trueself.assertTrue(a)def test04(self):"'失败案例'"a = "上海 - 悠悠"b = "yoyo"self.assertEqual(a, b)if __name__ == "__main__":unittest.main()
2.执行结果如下:
Failure
Expected :'\xe4\xb8\x8a\xe6\xb5\xb7-\xe6\x82\xa0\xe6\x82\xa0'
Actual :'yoyo'
<Click to see difference>Traceback (most recent call last):
File "D:\test\yoyotest\kecheng\test12.py", line 27, in test04
self.assertEqual(a, b)
AssertionError: '\xe4\xb8\x8a\xe6\xb5\xb7-\xe6\x82\xa0\xe6\x82\xa0' != 'yoyo'
3.执行的结果,中文的编码不对,没正常显示中文,遇到这种情况,可以自定义异常输出
二、自定义异常
1.以assertEqual为例分析:
assertEqual(self, first, second, msg=None)
Fail if the two objects are unequal as determined by the '==' operator.
2.翻译: 如果两个对象不能相等,就返回失败,相当于return:first == second
3.这里除了相比较的两个参数first和second,还有第三个参数msg=None,这个msg参数就是遇到异常自定义输出信息
三、unittest常用的断言方法
1.assertEqual(self, first, second, msg=None)
--判断两个参数相等: first == second
2.assertNotEqual(self, first, second, msg=None)
--判断两个参数不相等: first != second
3.assertIn(self, member, container, msg=None)
--判断两个字符串是否包含: member in container
4.assertNotIn(self, member, container, msg=None)
--判断字符串是否不包含: member not in container
5.assertTrue(self, expr, msg=None)
--判断是否为真: expr is True
6.assertFalse(self, expr, msg=None)
--判断是否为假:expr is False
7.assertIsNone(self, obj, msg=None)
--判断是否为None:obj is None
8.assertIsNotNone(self, obj, msg=None)
--判断是否不为None: obj is Not None
四、unittest所有断言方法
1.下面是unittest框架支持的所有断言方法,有兴趣的同学可以慢慢看。
| assertAlmostEqual(self, first, second, places=None, msg=None, delta=None)
| Fail if the two objects are unequal as determined by their
| difference rounded to the given number of decimal places
| (default 7) and comparing to zero, or by comparing that the
| between the two objects is more than the given delta.
|
| Note that decimal places (from zero) are usually not the same
| as significant digits (measured from the most signficant digit).
|
| If the two objects compare equal then they will automatically
| compare almost equal.
|
| assertAlmostEquals = assertAlmostEqual(self, first, second, places=None, msg=None, delta=None)
|
| assertDictContainsSubset(self, expected, actual, msg=None)
| Checks whether actual is a superset of expected.
|
| assertDictEqual(self, d1, d2, msg=None)
|
| assertEqual(self, first, second, msg=None)
| Fail if the two objects are unequal as determined by the '=='
| operator.
|
| assertEquals = assertEqual(self, first, second, msg=None)
|
| assertFalse(self, expr, msg=None)
| Check that the expression is false.
|
| assertGreater(self, a, b, msg=None)
| Just like self.assertTrue(a > b), but with a nicer default message.
|
| assertGreaterEqual(self, a, b, msg=None)
| Just like self.assertTrue(a >= b), but with a nicer default message.
|
| assertIn(self, member, container, msg=None)
| Just like self.assertTrue(a in b), but with a nicer default message.
|
| assertIs(self, expr1, expr2, msg=None)
| Just like self.assertTrue(a is b), but with a nicer default message.
|
| assertIsInstance(self, obj, cls, msg=None)
| Same as self.assertTrue(isinstance(obj, cls)), with a nicer
| default message.
|
| assertIsNone(self, obj, msg=None)
| Same as self.assertTrue(obj is None), with a nicer default message.
|
| assertIsNot(self, expr1, expr2, msg=None)
| Just like self.assertTrue(a is not b), but with a nicer default message.
|
| assertIsNotNone(self, obj, msg=None)
| Included for symmetry with assertIsNone.
|
| assertItemsEqual(self, expected_seq, actual_seq, msg=None)
| An unordered sequence specific comparison. It asserts that
| actual_seq and expected_seq have the same element counts.
| Equivalent to::
|
| self.assertEqual(Counter(iter(actual_seq)),
| Counter(iter(expected_seq)))
|
| Asserts that each element has the same count in both sequences.
| Example:
| - [0, 1, 1] and [1, 0, 1] compare equal.
| - [0, 0, 1] and [0, 1] compare unequal.
|
| assertLess(self, a, b, msg=None)
| Just like self.assertTrue(a < b), but with a nicer default message.
|
| assertLessEqual(self, a, b, msg=None)
| Just like self.assertTrue(a <= b), but with a nicer default message.
|
| assertListEqual(self, list1, list2, msg=None)
| A list-specific equality assertion.
|
| Args:
| list1: The first list to compare.
| list2: The second list to compare.
| msg: Optional message to use on failure instead of a list of
| differences.
|
| assertMultiLineEqual(self, first, second, msg=None)
| Assert that two multi-line strings are equal.
|
| assertNotAlmostEqual(self, first, second, places=None, msg=None, delta=None)
| Fail if the two objects are equal as determined by their
| difference rounded to the given number of decimal places
| (default 7) and comparing to zero, or by comparing that the
| between the two objects is less than the given delta.
|
| Note that decimal places (from zero) are usually not the same
| as significant digits (measured from the most signficant digit).
|
| Objects that are equal automatically fail.
|
| assertNotAlmostEquals = assertNotAlmostEqual(self, first, second, places=None, msg=None, delta=None)
|
| assertNotEqual(self, first, second, msg=None)
| Fail if the two objects are equal as determined by the '!='
| operator.
|
| assertNotEquals = assertNotEqual(self, first, second, msg=None)
|
| assertNotIn(self, member, container, msg=None)
| Just like self.assertTrue(a not in b), but with a nicer default message.
|
| assertNotIsInstance(self, obj, cls, msg=None)
| Included for symmetry with assertIsInstance.
|
| assertNotRegexpMatches(self, text, unexpected_regexp, msg=None)
| Fail the test if the text matches the regular expression.
|
| assertRaises(self, excClass, callableObj=None, *args, **kwargs)
| Fail unless an exception of class excClass is raised
| by callableObj when invoked with arguments args and keyword
| arguments kwargs. If a different type of exception is
| raised, it will not be caught, and the test case will be
| deemed to have suffered an error, exactly as for an
| unexpected exception.
|
| If called with callableObj omitted or None, will return a
| context object used like this::
|
| with self.assertRaises(SomeException):
| do_something()
|
| The context manager keeps a reference to the exception as
| the 'exception' attribute. This allows you to inspect the
| exception after the assertion::
|
| with self.assertRaises(SomeException) as cm:
| do_something()
| the_exception = cm.exception
| self.assertEqual(the_exception.error_code, 3)
|
| assertRaisesRegexp(self, expected_exception, expected_regexp, callable_obj=None, *args, **kwargs)
| Asserts that the message in a raised exception matches a regexp.
|
| Args:
| expected_exception: Exception class expected to be raised.
| expected_regexp: Regexp (re pattern object or string) expected
| to be found in error message.
| callable_obj: Function to be called.
| args: Extra args.
| kwargs: Extra kwargs.
|
| assertRegexpMatches(self, text, expected_regexp, msg=None)
| Fail the test unless the text matches the regular expression.
|
| assertSequenceEqual(self, seq1, seq2, msg=None, seq_type=None)
| An equality assertion for ordered sequences (like lists and tuples).
|
| For the purposes of this function, a valid ordered sequence type is one
| which can be indexed, has a length, and has an equality operator.
|
| Args:
| seq1: The first sequence to compare.
| seq2: The second sequence to compare.
| seq_type: The expected datatype of the sequences, or None if no
| datatype should be enforced.
| msg: Optional message to use on failure instead of a list of
| differences.
|
| assertSetEqual(self, set1, set2, msg=None)
| A set-specific equality assertion.
|
| Args:
| set1: The first set to compare.
| set2: The second set to compare.
| msg: Optional message to use on failure instead of a list of
| differences.
|
| assertSetEqual uses ducktyping to support different types of sets, and
| is optimized for sets specifically (parameters must support a
| difference method).
|
| assertTrue(self, expr, msg=None)
| Check that the expression is true.
|
| assertTupleEqual(self, tuple1, tuple2, msg=None)
| A tuple-specific equality assertion.
|
| Args:
| tuple1: The first tuple to compare.
| tuple2: The second tuple to compare.
| msg: Optional message to use on failure instead of a list of
| differences.
转:https://www.cnblogs.com/yoyoketang/p/6691270.html
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