在 Python 中模拟子进程调用
问题描述
我有一个方法 (run_script) 想要测试.具体来说，我想测试对 subprocess.Popen 的调用是否发生.测试是否使用某些参数调用 subprocess.Popen 会更好.但是，当我运行测试时，我得到 TypeError: 'tuple' object is not callable.
I have a method (run_script) would like to test. Specifically I want to test that a call to subprocess.Popenoccurs. It would be even better to test that subprocess.Popen is called with certain parameters. When I run the test however I get TypeError: 'tuple' object is not callable.
如何测试我的方法以确保 subprocess 确实是使用模拟调用的?
How can I test my method to ensure that subprocess is actually being called using mocks?
@mock.patch('subprocess.Popen')
def run_script(file_path):
process = subprocess.Popen(['myscript', -M, file_path], stdout=subprocess.PIPE)
output,err = process.communicate()
return process.returncode
def test_run_script(self, mock_subproc_popen):
mock_subproc_popen.return_value = mock.Mock(communicate=('ouput','error'), returncode=0)
am.account_manager("path")
self.assertTrue(mock_subproc_popen.called)
解决方案
你在 run_script 函数上使用补丁装饰器对我来说似乎很不寻常，因为你没有在那里传递模拟参数.
It seems unusual to me that you use the patch decorator over the run_script function, since you don't pass a mock argument there.
这个怎么样:
def run_script(file_path):
process = subprocess.Popen(['myscript', -M, file_path], stdout=subprocess.PIPE)
output,err = process.communicate()
return process.returncode
@mock.patch('subprocess.Popen')
def test_run_script(self, mock_subproc_popen):
process_mock = mock.Mock()
attrs = {'communicate.return_value': ('output', 'error')}
process_mock.configure_mock(**attrs)
mock_subproc_popen.return_value = process_mock
am.account_manager("path") # this calls run_script somewhere, is that right?
self.assertTrue(mock_subproc_popen.called)
现在，您模拟的 subprocess.Popen 似乎返回一个元组，导致 process.communicate() 引发 TypeError: 'tuple' object is not callable..所以最重要的是将mock_subproc_popen上的return_value弄的恰到好处.
Right now, your mocked subprocess.Popen seems to return a tuple, causeing process.communicate() to raise TypeError: 'tuple' object is not callable.. Therefore it's most important to get the return_value on mock_subproc_popen just right.
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