我想我错过了“thenReturn”部分的语法。我应该为源代码写些什么呢？

下面是源代码：

@Test
public void testGetUserByEmail() {
    String email = "mail";
    when(storeService.search(Mockito.anyString())).thenReturn(Mockito.any(Store.class));
    ModelAndView mav = storeController.search(email);
    Assert.assertEquals("userDetail", mav.getViewName());
}

服务是这样的：

public List<Store> listAllStore(){
    logger.info("Before add repository to show all");
    List<Store> all_stores=(List<Store>) storeRepo.findAll();
    logger.info("After add repository to show all");
    logger.info(all_stores);
    return all_stores;
}