使用后@patch
在我的装饰器上它不再起作用了。我想进行一个失败并引发异常的调用,以便我可以检查我的装饰器是否正在捕获此异常,并正在调用某个函数。
mock do_sth_in_db
让它引发异常是很容易的部分,但是在模拟这个方法之后,它不再被装饰——所以即使它引发了一个异常,也不会发生任何事情,因为它没有 try/except
阻止了。
TLDR:我想在我的模拟函数上放回 @decorator。
my.py
from my_decorator import transaction
class MyClass():
@transaction
def do_sth_in_db(self):
print('Did something in DB')
my_decorator.py
import functools
def rollback_func():
print('666 rollback fun called')
def push_to_db_func():
print('777 I have changed database')
def transaction(func):
functools.wraps(func)
def wrapper(*args,**kwargs):
try:
func(*args, **kwargs)
push_to_db_func()
print('worked')
except Exception:
rollback_func()
print('not worked, did rollback')
return wrapper
测试.py
import unittest
from mock import Mock, patch, MagicMock
from my import MyClass
from my_decorator import transaction
class TestMyRollback(unittest.TestCase):
@patch('my.MyClass.do_sth_in_db')
@patch('my_decorator.rollback_func')
@patch('my_decorator.push_to_db_func')
def test_rollback(self, push_to_db_func_mock, roll_back_func_mock, do_sth_in_db_mock):
cons = MyClass()
cons.do_sth_in_db()
do_sth_in_db_mock.assert_called_once()
## needs decorator to work
#push_to_db_func_mock.assert_called_once()
#roll_back_func_mock.assert_not_called()
##
#roll_back_func_mock.assert_called_once()
#push_to_db_func_mock.assert_not_called()
最佳答案
执行此操作的方法在 How to mock a decorated function 中有所描述。 .由于可能不完全清楚如何将其应用于当前问题,以下是工作代码:
import unittest
from unittest.mock import patch
from my_decorator import transaction
from my import MyClass
class TestMyRollback(unittest.TestCase):
@patch('my.MyClass.do_sth_in_db')
@patch('my_decorator.rollback_func')
@patch('my_decorator.push_to_db_func')
def test_rollback(self, push_to_db_func_mock,
roll_back_func_mock, do_sth_in_db_mock):
# this line re-applies the decorator to the mocked function
MyClass.do_sth_in_db = transaction(do_sth_in_db_mock)
cons = MyClass()
cons.do_sth_in_db()
do_sth_in_db_mock.assert_called_once()
push_to_db_func_mock.assert_called_once()
roll_back_func_mock.assert_not_called()
# test the exception case
push_to_db_func_mock.reset_mock() # have to reset the mocks
roll_back_func_mock.reset_mock()
# this is still the mock for the undecorated function
do_sth_in_db_mock.side_effect = [Exception]
cons.do_sth_in_db()
roll_back_func_mock.assert_called_once()
push_to_db_func_mock.assert_not_called()
关于python - 具有装饰器的模拟功能。再次使用相同的装饰器来装饰 Mock 对象并保持它是 Mock,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/61699871/