用Python unittest模拟side_effect

Question

I'm trying to mock out my requests.get to have a status code of 200 and make history[0].status_code trigger an IndexError (since there were no redirects). I'm able to get status_code to return 200 , but when I mock out history with the desired side effect, the IndexError is not triggered.

@patch('requests.get')
def test_no_redirect(self, mock_requests):
    mock_requests.return_value.status_code = 200
    mock_requests.history[0].status_code.side_effect = IndexError()

    response = requests.get('example.com')

    self.assertRaises(IndexError, response.history[0].status_code)            
    self.assertTrue(200, response.status_code)

Answer 1

Ok, I checked the code and I'd like to mention a few things.

First of all assertRises method receives callable as the second parameter ;) Its definition looks like this

def assertRaises(self, excClass, callableObj=None, *args, **kwargs):

The second thing, if you are mocking status_code using

mock_requests.return_value.status_code = 200

why not to try the same with history:

mock_requests.return_value.history = []

We are using the real list instead of some kind of mock, so I think that it's even better. The test method could look like this:

@patch('requests.get')
def test_no_redirect(self, mock_requests):
    mock_requests.return_value.status_code = 200
    mock_requests.return_value.history = []

    mock_requests.history[0].status_code.side_effect = IndexError

    response = requests.get('example.com')

    self.assertRaises(IndexError, lambda: response.history[0])
    self.assertTrue(200, response.status_code)