How to Mock Requests and Responses

Introduction

Unit testing in Python often involves mocking external dependencies to simulate real-world scenarios. Mocking allows us to control the behavior of these dependencies, providing greater stability and predictability to our tests. This article demonstrates how to mock Python's requests module and its responses to facilitate effective unit testing.

Step 1: Mocking Requests Module

To mock the requests module, utilize the mock module from the standard library:

import mock

Create a mock object for the requests module in the setup phase of the test method:

mockedRequests = mock.Mock()

Configure the mocked object to return specific responses for different URLs when the get() method is called:

mockedRequests.get.side_effect = [
    # First URL: Return 'a response'
    mock.Mock(status_code=200, text='a response'),
    # Second URL: Return 'b response'
    mock.Mock(status_code=200, text='b response'),
    # Third URL: Return 'c response'
    mock.Mock(status_code=200, text='c response')
]

Step 2: Calling the View

With the requests module mocked, call the function in the view that makes the requests:

res1 = mockedRequests.get('aurl')
res2 = mockedRequests.get('burl')
res3 = mockedRequests.get('curl')

Step 3: Verifying the Responses

Since the requests module is mocked, responses can be easily checked for the expected values:

self.assertEqual(res1.text, 'a response')
self.assertEqual(res2.text, 'b response')
self.assertEqual(res3.text, 'c response')