How to mock HTTPError response in Python unit test

Question

I would like to write a unit test case for HTTPError exception part based on the error response content I get. But I have now idea how I can mock the response so that the unit test can reach doSomething1() instead of doSomething2().

foo.py

def get_result_from_API():  
   #Try to call API here...

def getSomething():
  try:
    result = get_result_from_API()
  except HTTPError as error:
    error_json = error.response.json()
    if error_json.get("error").get("code") == "00001":
      doSomething1()
    else:
      doSomething2()
      raise error

Unit Test

@patch('foo.doSomething2')
@patch('foo.doSomething1')
@patch('foo.get_result_from_API')    
def testGetSomething(get_result_from_API,doSomething1,doSomething2):
  mock_response = Mock()
  mock_response.return_value = {  
      "error":{                            
          "code": "00001",
          "message": "error message for foo reason"            
      }
  }
  get_result_from_API.side_effect = HTTPError(response=mock_response)

  with self.assertRaises(HTTPError):
    foo.getSomething()

  doSomething1.assert_called_once()

The current result is that doSomething1() is not called where as doSomething2() is called.

What's not working as expected? What error messaged do you see? Where is the code getting to? How have you tried to debug so far? — mackorone, Jan 22 '22 at 08:03
The real code is somehow complicated. But it seems doSomething2() is called but doSomething1() is not. I would like the unit test to run through doSomething1(). — Zhuang Paulus, Jan 24 '22 at 01:44
I suggest you add print statements to your program to debug. Print out `error_json`. Is it what you expect? Print out `error_json.get("error")`. Is that what you expect? Etc. — mackorone, Jan 25 '22 at 05:13

score -1 · Answer 1 · answered Sep 08 '22 at 18:16

Since the getSomething function calls:

error_json = error.response.json()

the solution is to mock the call to .json()

  mock_response.json.return_value = {  
      "error":{                            
          "code": "00001",
          "message": "error message for foo reason"            
      }
  }

As it was originally written, getSomething would have had to have called response() directly.

error_json = error.response()

Here is a more generic example:

>>> from unittest.mock import Mock                                                        
>>> mock_response = Mock() 
                                                               
>>> mock_response.return_value = {"hello": "world"}                                       
>>> mock_response()  # call response() directly
{'hello': 'world'}

>>> mock_response.json()  # no return_value is assigned to the json() call
<Mock name='mock.json()' id='4407756744'>

>>> mock_response.json.return_value = {"hello": "universe"} # assign a json() return_value                              
>>> mock_response.json()                                                              
{'hello': 'universe'}

If you want, you can even do this while instantiating Mock:

How to mock HTTPError response in Python unit test

1 Answers1