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Now you have multiple tests you are probably feeling pretty good about your progress. However there are other ways to improve code efficiency further — you may notice that you've so far had to include a setUp() and a tearDown() method in each test file, going by the current constructs we've seen in this series. If you have several dozen tests then that’s a lot of code duplication! In this article we'll look at how to put the setUp()/tearDown() code common to all tests into a TestBase class, which can then be imported into each individual test file.


To start with, create a new file called test_base.py, in the same directory as your existing test cases.

Next, move your important statements that relate to the common setup (unittest, Marionette and time) into the file, along with a TestBase class containing the setUp() and tearDown() methods, and associated common helper functions (such as unlock_screen()). The file should look something like this:

import time
import unittest
from marionette import Marionette

class TestBase(unittest.TestCase):

    def unlock_screen(self):

    def kill_all(self):
             // Kills all running apps, except the homescreen.
             function killAll() {
               let manager = window.wrappedJSObject.AppWindowManager;

               let apps = manager.getApps();
               for (let id in apps) {
                 let origin = apps[id].origin;
                 if (origin.indexOf('verticalhome') == -1) {
             // return true so execute_async_script knows the script is complete

    def setUp(self):
         # Create the client for this session. Assuming you're using the default port on a Marionette instance running locally
        self.marionette = Marionette()

        # Unlock the screen

        # kill all open apps

        # Switch context to the homescreen iframe and tap on the contacts icon
        home_frame = self.marionette.find_element('css selector', 'div.homescreen iframe')

    def tearDown(self):
        # Close the Marionette session now that the test is finished

Updating your test files

With your test_base.py file created, you need to import TestBase into your test files, and the test classes need to be changed to extend the TestBase class:

import unittest
from marionette import Wait
from marionette import By
from test_base import TestBase
class TestContacts(TestBase):

    def test(self):
        # Tests in here
if __name__ == '__main__':

Try running your test file again.

It may not look like much now but when you have dozens or hundreds of tests this really saves a lot of duplicate code.

Document Tags and Contributors

Contributors to this page: chrisdavidmills, zac_c, Tingyu
Last updated by: chrisdavidmills,