new_contents: # This Source Code Form is subject to the terms of the Mozilla Public
  # License, v. 2.0. If a copy of the MPL was not distributed with this
  # file, You can obtain one at http://mozilla.org/MPL/2.0/.
  
  from marionette import MarionetteTestCase
  from puppeteer import Puppeteer
  
  class FirefoxTestCase(MarionetteTestCase):
      """
      Test case that adds a Puppeteer object to test scope.
      """
      def __init__(self, *args, **kwargs):
          MarionetteTestCase.__init__(self, *args, **kwargs)
          self.puppeteer = Puppeteer()
  
      def setUp(self, *args, **kwargs):
          MarionetteTestCase.setUp(self, *args, **kwargs)
          self.puppeteer.set_client(self.marionette)
  
      def tearDown(self, *args, **kwargs):
          self.puppeteer.client = None
          MarionetteTestCase.tearDown(self, *args, **kwargs)
  
  
subject: Add testcase.py