Android: How do I reset/clear application preferences during unit testing?

Question

I want to start with a consistent test environment so I need to reset/clear my preferences. Here's the SetUp for test I have so far. It's not reporting any errors, and my tests pass, but the preferences are not being cleared.

I'm testing the "MainMenu" activity, but I temporarily switch to the OptionScreen activity (which extends Android's PreferenceActivity class.) I do see the test correctly open the OptionScreen during the run.

 public class MyTest extends ActivityInstrumentationTestCase2<MainMenu> { 

...

    @Override     protected void setUp() throws Exception {     super.setUp();      Instrumentation instrumentation = getInstrumentation();     Instrumentation.ActivityMonitor monitor = instrumentation.addMonitor(OptionScreen.class.getName(), null, false);      StartNewActivity(); // See next paragraph for what this does, probably mostly irrelevant.     activity = getActivity();     SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(activity);     settings.edit().clear();     settings.edit().commit(); // I am pretty sure this is not necessary but not harmful either. 

StartNewActivity Code:

    Intent intent = new Intent(Intent.ACTION_MAIN);     intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);     intent.setClassName(instrumentation.getTargetContext(),             OptionScreen.class.getName());     instrumentation.startActivitySync(intent);     Activity currentActivity = getInstrumentation()             .waitForMonitorWithTimeout(monitor, 5);     assertTrue(currentActivity != null); 

Thanks!

Answer 1

The problem is that you aren't saving the original editor from the edit() call, and you fetch a new instance of the editor and call commit() on that without having made any changes to that one. Try this:

Editor editor = settings.edit(); editor.clear(); editor.commit(); 

Answer 2

Answer is here, android unit test: clearing prefs before testing activity

Call,

this.getInstrumentation().getTargetContext()