Python 错误 异常

8 错误，调试和测试

8.1错误处理

所有的异常来自 BaseException

记录错误 ：

# err_logging.py

import logging

def foo(s):

return 10 / int(s)

def bar(s):

return foo(s) * 2

def main():

try:

bar('0')

except Exception as e:

logging.exception(e)

main()

print('END')

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抛出错误给上级

# err_reraise.py

def foo(s):

n = int(s)

if n==0:

raise ValueError('invalid value: %s' % s)

return 10 / n

def bar():

try:

foo('0')

except ValueError as e:

print('ValueError!')

raise

bar()

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8.3单元测试

unittest.TestCase内置了许多方法