### Question:
DataService implements Serializable { public abstract Collection<Product> getAllProducts();  abstract Collection<Product> getAllProducts(); abstract Collection<Category> getAllCategories(); abstract void updateProduct(Product p); abstract void deleteProduct(int productId); abstract Product getProductById(int productId); abstract void updateCategory(Category category); abstract void deleteCategory(int categoryId); static DataService get();  }### Answer:
@Test public void testDataServiceCanFetchProducts() throws Exception { assertFalse(service.getAllProducts().isEmpty()); }