Python – 单元测试中的 assertLess()函数

Python中的 assertLess() 是一个 unittest 库函数，用于单元测试以检查第一个给定值是否小于第二个值。该函数将采用三个参数作为输入，并根据断言条件返回一个布尔值。

该函数检查第一个给定的值是否小于第二个值，如果是，则返回 true，如果第一个值不小于第二个值，则返回 false。

Syntax: assertLess(first, second, message=None) 

Parameters: assertLess() accept three parameters which are listed below with explanation:

• first: first input value (integer)
• second:  second input value (integer)
• message: a string sentence as a message which got displayed when the test case got failed.

下面列出了一个示例，说明了给定断言函数的正面和负面测试用例：

示例 1 ：如果第一个值不小于第二个值。

Python3

# test suite
import unittest
  
class TestStringMethods(unittest.TestCase):
      
    # negative test function to test if
    # values1 is less than value2
    def test_negativeForLess(self):
        first = 6
        second = 5
          
        # error message in case if test case got failed
        message = "first value is not less that second value."
          
        # assert function() to check if values1 is
        # less than value2
        self.assertLess(first, second, message)
  
# main for function call
if __name__ == '__main__':
    unittest.main()

输出：

F
======================================================================
FAIL: test_negativeForLess (__main__.TestStringMethods)
———————————————————————-
Traceback (most recent call last):
 File “p1.py”, line 13, in test_negativeForLess
   self.assertLess(first, second, message)
AssertionError: 5 not less than 5 : first value is not less that second value.

———————————————————————-
Ran 1 test in 0.000s

FAILED (failures=1)

示例 2：如果第一个给定值小于第二个值

Python

# test suite
import unittest
  
class TestStringMethods(unittest.TestCase):
      
    # positive test function to test if 
    # values are almost equal with place
    def test_positiveForLess(self):
        first = 2
        second = 3
          
        # error message in case if test case got failed
        message = "first value is not less that second value."
          
        # assert function() to check if values1 is
        # less than value2
        self.assertLess(first, second, message)
  
# main for function call
if __name__ == '__main__':
    unittest.main()

输出：

.
———————————————————————-
Ran 1 test in 0.000s

OK