Support using identifiers generated by database as method arguments

[IlyaMuravjov]

Description

For reproduceable tests for methods that can read database and accept identifiers, we want to first fill up the database, take some identifier generated by the database and then pass that identifier to the method under test. That also solves the problem of fuzzer not always being able to guess identifiers that are used by the database, for example, when database uses random UUIDs.

How to test

Manual tests

Generate tests for OrderService#deleteOrderById(Long) from spring-boot-testing-main project, there should be test that looks like this:

@Test
@DisplayName("deleteOrderById: id = orderRepository.save(id = Order()).id -> return true")
public void testDeleteOrderByIdReturnsTrue() throws ClassNotFoundException, IllegalAccessException, NoSuchFieldException, InvocationTargetException, NoSuchMethodException {
    OrderService orderService = ((OrderService) applicationContext.getBean("orderService"));
    OrderRepository orderRepository = ((OrderRepository) applicationContext.getBean("orderRepository"));
    Order order = new Order();
    orderRepository.save(order);
    OrderRepository orderRepository1 = ((OrderRepository) applicationContext.getBean("orderRepository"));
    Order order1 = new Order();
    order1.setQty(1);
    order1.setBuyer("");
    order1.setPrice(Double.NEGATIVE_INFINITY);
    order1.setId(0L);
    Order order2 = ((Order) orderRepository1.save(order1));
    Long id = ((Long) getFieldValue(order2, "com.rest.order.models.Order", "id"));

    boolean actual = orderService.deleteOrderById(id);

    assertTrue(actual);
}

Self-check list

• I've set the proper labels for my PR (at least, for category and component).
• PR title and description are clear and intelligible.
• I've added enough comments to my code, particularly in hard-to-understand areas.
• The functionality I've repaired, changed or added is covered with automated tests.
• Manual tests have been provided optionally.
• The documentation for the functionality I've been working on is up-to-date.