Mocking modules from boto in python

Question

I am trying to write a unit test for a class that looks like below.

import boto
class ToBeTested:
    def location(self, eb):
        return eb.create_storage_location() 

    def some_method(self):
        eb = boto.beanstalk.connect_to_region(region, access_key, secret_key)
        location(eb)

Is there a way to mock boto.beanstalk.connect_to_region return value and finally mocking create_storage_location? I am new to patch and mock in python, so I have no idea how could I go about doing that. Could someone please let me know if there is a way to do this?

Thanks much!

Answer 1

The idea is to patch connect_to_region() so that it returns a Mock object, then you can define whatever methods you want on the mock, example:

import unittest

from mock import patch, Mock


class MyTestCase(unittest.TestCase):
    @patch('boto.beanstalk.connect_to_region')
    def test_boto(self, connect_mock):
        eb = Mock()
        eb.create_storage_location.return_value = 'test'
        connect_mock.return_value = eb

        to_be_tested = ToBeTested()
        # assertions

See also:

• An Introduction to Mocking in Python

Hope that helps.