@Override
 protected void tearDown() throws Exception {
   AuthenticationSettings.INSTANCE.setSharedPrefPackageName(null);
   DefaultTokenCacheStore store = new DefaultTokenCacheStore(ctx);
   store.removeAll();
   super.tearDown();
 }
 @Override
 protected void setUp() throws Exception {
   super.setUp();
   ctx = this.getInstrumentation().getContext();
 }