在Python中模拟子进程调用

我有一个方法(run_script)想测试.具体来说,我想测试一下对subprocess.Popenoccurs的调用.测试subprocess.Popen甚至更好用某些参数调用.当我运行测试时,我得到TypeError：’tuple’对象不可调用.

如何测试我的方法以确保实际使用模拟调用子进程？

@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)

解决方法:

在run_script函数中使用补丁装饰器对我来说似乎不寻常,因为你没有在那里传递一个mock参数.

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,你的模拟subprocess.Popen似乎返回一个元组,导致process.communicate()引发TypeError：’tuple’对象不可调用.因此,最重要的是让mock_subproc_popen上的return_value恰到好处.