python3 try异常 断言assert

try:
f = open("hello1.txt",'r')

except Exception as e:
print (e)

try:
print (a)
except Exception as e:
print(e)

     

raise抛出一个自定义异常，抛出的异常类型必须是python内的类型。

断言assert

import unittest
def div(a, b):
return a / b

class TestDiv(unittest.TestCase):

def test_1_div_1(self):
self.assertEqual(div(1, 1), 1 / 1)

def test_3_div_4(self):
self.assertEqual(div(3, 4), 3 / 4)

def test_3_div_0(self):
self.assertRaises(ZeroDivisionError, div, 1, 0)

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