ElifutDataStore extends SQLiteOpenHelper { public void deleteAll() { for (Persistable.Converter<?> converter : converterMap.values()) { db.execute("DELETE FROM " + converter.tableName()); } } ElifutDataStore(Context context, SqlBrite sqlBrite,
      List<Persistable.Converter<?>> converters); @Override void onCreate(SQLiteDatabase db); @Override void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion); long create(Persistable persistable); void create(Persistable... persistables); void create(List<? extends Persistable> persistables); int update(Persistable persistable, int id); int delete(Persistable persistable, int id); List<T> query(Class<T> type); List<T> query(Class<T> type, int... rowIds); List<T> query(Class<T> type, String whereClause, String... args); @Nullable T queryOne(Class<T> type, int rowId); Observable<List<T>> observe(Class<T> type); Observable<List<T>> observe(
      Class<T> type, String whereClause, String... args); Persistable.Converter<T> converterForType(Class<?> type); void deleteAll();  }
@Test public void testDeleteAll() { service.create(TestFixtures.GREMIO, TestFixtures.INTERNACIONAL); service.create(TestFixtures.GORNALDO, TestFixtures.PELE); service.deleteAll(); List<? extends Club> clubs = service.query(AutoValueClasses.CLUB); List<? extends Player> players = service.query(AutoValueClasses.PLAYER); assertThat(clubs).isEmpty(); assertThat(players).isEmpty(); }