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/.
  
  import os
  import cleanslate
  
  
  def test_pid_exists():
      assert cleanslate.pid_exists(os.getpid()) is True
      assert cleanslate.pid_exists(999999) is False
  
subject: Add tests.