Python unittest – assertIsNone()函数
Python中的assertIsNone () 是一个 unittest 库函数，用于在单元测试中检查输入值是否为None 。该函数将两个参数作为输入，并根据断言条件返回一个布尔值。如果输入值等于 None， assertIsNone () 将返回 true，否则返回 false。
Syntax: assertIsNone(testValue, message)
Parameters: assertIsNone() accept two parameters which are listed below with explanation:
- testValue: test variable as the input value to check equality with None
- message: a string sentence as a message which got displayed when the test case got failed.
下面列出了两个不同的示例，说明了给定断言函数的正负测试用例：
示例 1：否定测试用例
Python3
# unit test case
import unittest
class DummyClass:
x = 5
class TestMethods(unittest.TestCase):
# test function
def test_negative(self):
firstValue = "geeks"
# error message in case if test case got failed
message = "Test value is not none."
# assertIsNone() to check that if input value is none
self.assertIsNone(firstValue, message)
if __name__ == '__main__':
unittest.main()Python3
# unit test case
import unittest
class DummyClass:
x = 5
class TestMethods(unittest.TestCase):
# test function
def test_positive(self):
firstValue = None
# error message in case if test case got failed
message = "Test value is not none."
# assertIsNone() to check that if input value is none
self.assertIsNone(firstValue, message)
if __name__ == '__main__':
unittest.main()输出：
F
======================================================================
FAIL: test_negative (__main__.TestMethods)
----------------------------------------------------------------------
Traceback (most recent call last):
File "p1.py", line 14, in test_negative
self.assertIsNone(firstValue, message)
AssertionError: 'geeks' is not None : Test value is not none.
----------------------------------------------------------------------
Ran 1 test in 0.000s
FAILED (failures=1)
示例 2：正面测试用例
Python3
# unit test case
import unittest
class DummyClass:
x = 5
class TestMethods(unittest.TestCase):
# test function
def test_positive(self):
firstValue = None
# error message in case if test case got failed
message = "Test value is not none."
# assertIsNone() to check that if input value is none
self.assertIsNone(firstValue, message)
if __name__ == '__main__':
unittest.main()
输出：
.
----------------------------------------------------------------------
Ran 1 test in 0.000s
OK
参考：https://docs。 Python.org/3/library/unittest.html