title: Reset iOS App content before executing tests
body: <p>I want to write tests for an iOS 8 app. The app starts in the simulator before the tests are run and it loads all possibly existing preferences and keychain items. As it's impossible to correctly test the app, when there always could be leftover preferences from earlier tests or manual usage of the simulator, I would like to reset the app every time before the tests are executed. How could I do this?</p>