Python mock patch doesn't work as expected for public method

问题:

I'm trying to patch a public method for my flask application but it doesn't seem to work.

Here's my code in mrss.feed_burner

def get_feed(env=os.environ):    return 'something' 

And this is how I use it

@app.route("/feed")     def feed():         mrss_feed = get_feed(env=os.environ)         response = make_response(mrss_feed)         response.headers["Content-Type"] = "application/xml"          return response 

And this is my test which it's not parsing.

def test_feed(self):     with patch('mrss.feed_burner.get_feed', new=lambda: '<xml></xml>'):         response = self.app.get('/feed')         self.assertEquals('<xml></xml>', response.data) 

回答1:

I believe your problem is that you're not patching in the right namespace. See where_to_patch documentation for unittest.mock.patch.

Essentially, you're patching the definition of get_feed() in mrss.feed_burner but your view handler feed() already has a reference to the original mrss.feed_burner.get_feed(). To solve this problem, you need to patch the reference in your view file.

Based on your usage of get_feed in your view function, I assume you're importing get_feed like so

view_file.py

from mrss.feed_burner import get_feed 

If so, you should be patching view_file.get_feed like so:

def test_feed(self):     with patch('view_file.get_feed', new=lambda: '<xml></xml>'):         ... 

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