How to test saving and restoring state of an android activity with Espresso?

Question

Is there a way of testing the save and restore state code of an activity programmatically ? I mean doing this :

How to test code built to save/restore Lifecycle of an A

Answer 1

You can rotate the screen and verify that the state is saved and restored properly.

private void rotateScreen() {
  Context context = InstrumentationRegistry.getTargetContext();
  int orientation 
    = context.getResources().getConfiguration().orientation;

  Activity activity = activityRule.getActivity();
  activity.setRequestedOrientation(
      (orientation == Configuration.ORIENTATION_PORTRAIT) ?
          ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE : 
          ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}

Full example: http://blog.sqisland.com/2015/10/espresso-save-and-restore-state.html