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Side Effects: Setting Up

Lee Gaines
Improve Your Tests With the Python Mock Object Library Lee Gaines 02:36
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00:00 I’m going to make a little more space in this file, just come down here, and we’ll write a new function. Let’s use the requests module, so we’ll import requests.

00:12 And with the theme of this calendar thing we have going on, we’ll define a function called get_holidays(). get_holidays() will take no parameters. And we’ll make a request, let’s say r = requests.get().

00:28 And let’s make up a little server here, let’s say we’re running on localhost/api/holidays.

00:37 If you’re not familiar with the requests module, it provides a library of functions to make HTTP requests and a lot more. But essentially, this r is making a GET request to this URL.

00:52 After it makes this GET request, it’ll check the status code. So we’ll say if r.status_code == 200—meaning a successful response—we’ll return that response as JSON, and anything else will just return None.

01:14 So we have this little get_holidays() function that hits an API, and who knows what this API does, but we check the response code. If it’s successful, we’ll return a dictionary of its JSON. And say we want to now test this function.

01:29 Let’s use the built-in unittest framework and we’ll go down and make a class called TestGetHolidays, and this will inherit from unittest.TestCase.

01:46 We will need to import unittest—let’s import unittest—and if you’re unfamiliar with the unittest framework, you have to create a class and then you define functions within that class for each test case.

02:02 So this class will represent all of our unit tests for the get_holidays() function—that’s why I named it get TestGetHolidays. And for our first test, let’s define a function called .test_get_holidays_connection().

02:20 You have to give it self. And this is where we start to play with the side effects, but before we do that, let’s just pass here for a second and let’s see what happens when we actually call this get_holidays() function as it is.

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