How to fill database in tests for Spring projects if smth different from CrudRepository is used?

[EgorkaKulikov]

Consider generating integration tests for the method in Spring project that interacts with the database. In such case we should save some data in the database and verify that it is processed correctly.

For example, if we test a method

 public Order getOrderById(Long id) {
        return orderRepository.findById(id).orElseThrow(() -> throwException(String.valueOf(id)));
    }

The following code is generated as a part of test method

Order order = new Order();
order.setId(1L);
order.setBuyer("#$\\\"'");
order.setPrice(0.0);
order.setQty(Integer.MAX_VALUE);
        
orderRepository.save(order);

This code is generated under the assumption that repositories in user project implement CrudRepository that has save method. This assumption is highly likely correct.

However, there is a marker interface Repository in Spring that does not have any specified method to save. What should we do?
Also, user may have some non-Spring libraries for database processing, like mybatis and it seems to be very difficult to deal with. Just one of the reasons is that some not compatible with H2 (used in concrete execution) dialect of SQL may be used.